On a reread, it seems clear that if SJL didn't go to Shorrolds, she went to the PoW. The basis for believing that she didn't go to 37SR is the fictitious client name, the lack of keys to get in, and the absence of reliable sightings of her there. Those we have are either unreliable in themselves, eg HR who never identified her in the first place then later made and retracted a claim of seeing her bundled into a car; or are themselves clearly derivative of HR's supposed sighting; and / or came years later.
So that leaves the PoW as the only likely destination.
If PoW was the destination, several people knew she was going there. CV knew, his partner knew, and the LL and his wife knew. According to CV - but only according to CV - two other people also knew, because they rang the pub asking after her.
We know the LL and his wife were gone before SJL ever left the office, so this leaves only CV and his partner who were both there and expecting her. We don't know if the pub was open or busy, but if not, and CV's partner went out, then it becomes apparent that SJL could have gone to an empty pub. If harm came to her there, then it was either at CV's hands, or those of someone else who intercepted her there. Whoever that might have been could have done so only with CV's connivance.
DV has anonymised CV's name because the unavoidable inference is that CV is either a killer or has assisted in covering up a killing. He speculates that maybe this was an accident rather than a murder, but I think this unlikely. If someone is accidentally killed, you don't immediately hide the body and lie to the police and everyone else. You dial 999. If SJL were injured in unsuspicious circumstances, this is what CV would surely have done. This suggests that the nature of her injuries was such that it would have been obvious she was being attacked at the time she died: ligature marks around her neck, disturbance to her clothing, bruising from being restrained, etc.
So CV realises he has to cover it up. He hastily hides the body where DV suggests, then when the police are told her stuff is at the pub, it is handed over with no comment except that she never turned up. A year later, CV is reinterviewed, and this time he adds an embellishment: that there were two calls for SJL to the pub.
AFAIK nobody else gave this information, so CV is the only source. It's much too late to try to trace the incoming calls. It seems possible that on being reinterviewed, he thought he'd better introduce a few red herrings. If the police were getting interested in the PoW, and perhaps starting to discount the Mr Kipper blind alley, maybe they have worked out where she probably did go. And that was to a pub with only him, CV, in it at that time. And he doesn't work there any more so he can't get retrieve or move the body now.
So he needed someone else to know she was going there too; someone who couldn't be traced. He tried to claim he was not changing his story by saying he'd given the phone number of these callers to the police a year ago. The police had no record of his having done so. The officers were reliable, so either they had made an almighty error, or CV was lying. Luckily for CV the former was assumed, and not long after, up pops JC into the frame.
DV has anonymised CV's name, but there seems no reason for him not to have anonymised his description too. He's described as a short fat, deaf old man, but what if he was 6'3" and 17 stone in 1986? What if he could obviously have overpowered SJL?
Between the lines, the best explanation for CV's ex furiously refusing to talk to DV or even his assistant could be fear of CV. Maybe she knows what he's capable of? She immediately calls on her husband for protection and he tells DV to clear off. I'd say she's frightened of someone.
Many of the whodunit theories about other famous cases falter because they can't put the "new" suspect at the scene. Yes it might have been X who was Jack the Ripper, but does any reliable witness or evidence credibly place X at the scene of at least one of the Ripper crimes? With AFAIK the exception of Charles Lechmere, no - so there is no reason to believe any of them. Another reason these theories fail is that they require people to have done things, or been in places, or had suppositious motivations for which there's no evidence.
The best argument for this being CV is that he has put himself at the potential scene of the crime. He does so in comparative safety because nobody, until DV, has intuited that the PoW even was the scene of any crime. The argument against the involvement of anyone else is not that it's only CV's account of that day that involves others, but that actually, nobody else need have been involved. Nobody else is necessary for it to have been CV.
If so then he has been a dangerous man for years, and the obvious question is where has he lived and worked since, and who else has gone missing nearby.