I was impressed. 'You're very well informed,' I said.

'It's my legs that don't work, not my brain. I like to make sure it stays that way. Some people call me nosy. I prefer to think of it as a healthy curiosity. What are you, anyway? Some kind of bailiff? And don't give me that stuff about being a representative of the conservatory company. You're far too smart for that. Besides, there's obviously been something very odd going on there. You're not just following up who you've sold conservatories to.'

I could have carried on bluffing, but I couldn't see the point. Diane deserved some kind of quid pro quo. 'I'm a private investigator,” I said. 'My partner and I investigate white-collar crime.'

'And this is the case of the missing conservatories, eh? Wonderful! You have made my week, Kate Brannigan.'

As I drove off towards Trafford Park, I began to suspect that Diane Shipley might just have made mine.

Brian Chalmers of PharmAce was less than thrilled when I told him the results of my work both inside and outside his factory and warehouse. He was furious with himself for employing a senior lab technician whose loyalty lay to his bank account rather than his boss. Unfortunately, because of my cock-up with the surveillance film, he didn't have any evidence other than my word, which wasn't enough for him to drag the guy into his office and fire him on the spot. So, since he had to take his anger out on someone, I got the lab technician's kicking. And because the client is always right (at least while he's actually in the room) I had to bite the bullet and stand on for the bollocking.

I let him rant for a good ten minutes, then offered to repeat the surveillance exercise over the weekend at a reduced rate. That took the wind out of his sails, as it was meant to. Unfortunately, as I left Chalmers' office, I passed one of the technicians I had dealt with during my short spell working undercover at PharmAce but, although he looked at me as if he ought to know me, he passed by without greeting me. Looked like I'd been lucky. The phenomenon of not recognizing people out of context had worked in my favour. After all, what would a temporary stock clerk be doing in the managing director's office, all suited up?

It was just before three when I pulled up outside the Thai boxing gym. My head felt like it was full of cogs and wheels all spinning out of sync, trying to assimilate everything that Diane Shipley had told me and make it fit what I'd been told at the other houses. None of it really made any sense so far. I know from bitter experience that when my mind is churning and fizzing, there's nothing better than some hard physical exercise. Which for me these days means Thai kick-boxing.

It started off as purely utilitarian. My friend Dennis the burglar pointed out to me that I needed self-defence skills. He wasn't so much thinking about the job I do as the neighbourhood where I live. He persuaded me to come along to the club where his adored teenage daughter is the junior champion. When I saw the outside of the building, a horrible, breeze-block construction like an overgrown Scout hut, I was deeply unimpressed. But inside, it's clean, warm and well-lit. And the women's coach, Karen, is a former world champion who gave up serious competition to have a family. One of the wildest sights in our club is watching her three-year-old toddling round the ring throwing kicks at people twice his size, and causing them a lot of grief.

I was in luck, for Karen was in the tiny cubicle she calls an office, desperate for an excuse to avoid doing the paperwork. She was in luck too, for I was so bagged off at the verbal beating I'd had from Brian Chalmers that I gave her the most challenging work-out I'd ever managed.

Left to their own devices, the tumblers in my brain started to slot into place. By the time we'd finished trading blows, I knew where I had to look next on the trail of the missing conservatories.

Since the Land Registry keeps office hours rather than supermarket ones, I couldn't have done anything more that afternoon, even supposing they didn't insist that you make a prior appointment to look at the registers. The real blow was that Ted had inconsiderately sold his conservatories to properties that were covered by two separate offices; the Warrington ones came under Birkenhead, the Stockport ones under Lytham St Anne's, an arrangement about as logical as having London covered by Southampton. Just to confuse things even more, the Lytham registry is in Birkenhead House… Ever get the impression they really don't want you to exercise your rights to examine their dusty tomes? However, I did manage to get an appointment in Birkenhead for the Monday morning. When I read over the list of addresses, the woman I spoke to sounded positively gleeful. It's a joy to deal with people who love their work. After sorting that out, I felt I could pursue Alexis's dodgy builder with a clear conscience.

I went home to change into something a little less threatening than a business suit. While I was there, I tried to ring T.R. Harris's solicitor, Mr. Graves. The number rang out without response. The idleness of some of the legal profession never ceases to amaze me. Twenty past four and everyone had knocked off for the day. Maybe Thursday was early closing day in Ramsbottom. I couldn't find T.R. Harris in the phone book, which was annoying but not too surprising, given the habits of builders.

My hair was still damp from my shower at the gym, so I gave it a quick blast with the hair dryer. I decided a couple of months ago to let it grow. Now it's reached my shoulders, but instead of growing longer, it just seems to get wilder. And I've noticed a couple of grey hairs in among the auburn. Some hair colours go grey gracefully, but auburn ain't one of them. So far, there are few enough to pull out, but I suspect it won't be long before I have to hit the henna, like my mother before me. Muttering under my breath, I chose a pair of russet trousers, a cream polo-neck angora and lambswool jumper and a tweedy jacket. Now the nights were drawing in, it was time for my favourite winter footwear, my dark tan cowboy boots that might have seen better days but fit like a pair of gloves. Just the thing for a trip to the horrid, nasty, windy, wet, dark countryside. If you have to abandon the city, you might at least be dressed for it. Remembering the lack of street lights out there, I slipped a small torch in my bag.

As I drove across town towards the motorway, I decided that I needed to track down the farmer who had sold the land to T.R. Harris in the first place. But on the way, I decided to check out Harris's premises. I wanted to know where I could lay hands on him once I had my ammunition.

134 Bolton High Road wasn't the builder's yard I'd been expecting. It was a corner shop, still open for the sale of bread, chocolate, cigarettes and anything else the forgetful had omitted to lay in for the evening's viewing. An old-fashioned bell on a coiled spring jangled as I opened the door. The teenage lad behind the counter looked up from his motor-bike magazine and gave me the once-over reserved for anyone who hadn't been crossing the threshold on a regular basis for the last fifteen years.

'I'm looking for a builder,' I said.

'Sorry, love, we don't sell them. There's no demand, you see.' He struggled to keep a straight face, but failed.

'I'm demanding,' I said. I waited for him to think of the reply.

He only took a few seconds. T bet you are, love. Can I help?'

'A builder called Harris. T R. Harris. This is the address I've got for him. Do you act as an accommodation address for people?'

He shook his head. 'Me mam won't stand on for it. She says people who won't use their own address must be up to no good. Tom Harris, the guy you're looking for, he rented one of the offices upstairs for a couple of months. Paid cash, an' all.'