The publicly-rehearsed facts of this case don’t really get us anywhere, not least because a number of them turn out not to be definite facts at all.
She seems to have left the office at 12.40pm on Monday 28th July, leaving only two clues as to where she was going. One was the desk diary entry noting a viewing with a non-existent person, Mr Kipper, and the other was a phone call to the pub where she had mislaid her diary and cheque book.
She may have gone to 37SR to meet Mr Kipper, but it’s not cut-and-dried that she did so. First, it’s not clear she even took the keys. Colleagues were later able to enter the house to search it, and when the police forensicated it the next day, regardless of how they got in, they found no evidence anyone had been inside. Second, it’s not clear she was seen outside 37SR either. The most-cited witness claimed to have heard people coming out of 37SR, which isn’t possible if she never went in. He later conceded it could have been from 33 that he heard people leaving. The e-fit looks like most 30-year-old men in 1986, and that and the description are markedly different from other witness accounts. Some were so vague as to timing they could have been describing MG’s visit and misremembering the time.
If we accept on an Occam’s Razor basis that she did go, the next difficulty is that several witnesses are adamant her car was at 123SR by 12.40 - meaning she went straight there. If she intended to go to 37SR, she instead went to 123SR when she left the office, i.e. headed in 180 degrees the wrong direction. She there met someone, a mile away from 37SR, then got a lift back to Shorrolds, leaving her car unlocked outside 123SR.
There are several anomalous sightings and non-sightings that afternoon in Stevenage Road. Sightings include the jogger who saw a BMW apparently driven by a woman either screaming or laughing, which may have been an LHD car driven by its male “passenger”. Another was a James Galway lookalike who told a cabbie he’d just seen a right ruck going on. Another is MJ’s sighting of a good looking couple. None of these people ever came forward. Another is a reported strange howl that the witness assumed at the time to be a cat. Non-sightings include the BT workers who never noticed her car being ditched a few feet from them, nor heard any ruck. Another is the non-sighting of her retrieving her car at about 2.30. This has to have happened because she was seen in it then, heading away from 123SR, by someone who actually knew her. This time undermines all the other sightings.
So what actually happened? Well, SJL would IMO not have wasted time going out to a viewing with a quantity so unknown he’d yet to be logged as a potential customer. Until someone had checked out his situation, credibility etc, nobody would know if he was a plausible buyer, so you’d waste no time showing him houses until all that was clear. Ergo, Mr Kipper - the kind of nickname her clique tended to acquire - was a mate, or a private non-Sturgis contact dangling some sort of opportunity. He could have been a sexual partner, actual or contemplated - SJL was four-timing AL the week before she disappeared.
Who this was is conjecture. There were three men’s prisons within 4.5 miles of where she lived and worked, who between them released 1 to 2 rapists per week. So by the end of July, there could have been 30 to 50 released that year, any of whom might have hung around Fulham. She cultivated prosperous men as contacts and some were never tracked down. She was engaged in but had cooled on a business venture with a friend financed by the husband, who went bankrupt 8 days later. She told relatives she had a big deal on and that a man she was in touch with was pressuring her.
Probably SJL was inveigled into meeting someone she knew, we don’t know how, who got her to drive to a place where she could be taken inside an unremarkable house, garage or other building and attacked. She was probably either raped and then murdered so she couldn’t ID or accuse her rapist, or just murdered. I suspect a garage or warehouse, because she could then have been transferred from one car to another and disposed of elsewhere. Or perhaps hidden under a floor, depending on the sort of building (if you take up the ground floor boards of a London house, underneath there is the dirt the house was built on). Her car was abandoned at some point, the sloppy parking suggesting either a hurry, a short stop or someone returning to it to remove evidence.
The conjecture is that this person was JC. The “evidence” the police give for this is completely laughable, and consists of hearsay, coached statements 14 years after the fact, and assertions of their own opinion presented as fact. The CPS looked at the police case and concluded there was no evidence JC and SJL had ever met. A better circumstantial case against JC is possible, but presenting the best circumstantial case publicly would involve the police admitting that they missed leads, clues and obvious lines of inquiry in 1986. Had they been followed, and if it was JC, these would have led them to him in 1986 and hence saved the life of SB 2 years later. So the reason the police's public case against Cannan is so feeble is that the more damningly comprehensive one is simply too embarrassing to make.
Given the complexity and compartmentalization of her life, it didn't have to be JC. It could have been some other business contact who did this, or it could have been any other of the locally-released rapists. All of these are conjectural killers who may not exist, so on an Occam’s Razor basis, you tend to give it to Cannan because he did. But even here, although he does actually exist, evidence he met her does not. And as plausible as the circumstantial case against him sounds, nobody ever tried to see if any similarly plausible case could be made against any similar local offender. So while it fits Cannan, it’s not clear who else it fits too.