It's interesting to focus on a detail like this because it so typifies the entire case.
The purse detail is telling. This is a woman who's spent a fair part of her morning chasing down her mislaid cheque book. She's going to do all that then literally immediately after, leave her purse in an unlocked car?
If WJ is correct, then all of the 37SR "witnesses" are nothing of the kind. There is simply no conceivable reason why, to go to 37SR which is north-east of the office, SJL would head off west, in exactly the wrong direction, leave her car outside 123SR unsecured with her purse in it, and then be driven back by A N Other to 37SR. It's 2.4 miles round the houses instead of 0.5 miles, and she then supposedly carried out a totally normal-looking viewing except that she got killed at some point.
Likewise BW has to be wrong. Although there's a window when WJ wasn't there during which the car could have moved, for BW to be right SJL's car had to have been brought back and misparked again in the identical place in order to look like it had been there all day.
Another witness who has to be wrong is the one who said she saw a couple in that part of Stevenage Road later that afternoon. If WJ is right, SJL and A N Other were already long gone and not coming back.
It doesn't get a lot better if you assume instead that the 37SR "sightings" are right. You sort of can't because they're inconsistent, but inconsistent as they are, they don't leave any room for WJ to be right.
Likewise if BW is right WJ is necessarily wrong.
This is not the only such example in this case. AL's account of the PoW is certainly inaccurate - he's given two that conflict and neither reconciles to KH/CV or MH's account. Either the stuff was lost on Friday at the pub or on Sunday at the pub, but it cannot have been lost at Mossop's on either day.
If it was lost at Mossop's on Friday how did it spend 48 hours travelling to the PoW on Sunday?
It can't have been lost at Mossop's on Sunday. Nobody has suggested they went out on Sunday night. SJL left the beach separately having ignored AL all weekend, went to her parents' house, then home. There's room in this for a 10.15 phone call but not for a meal at that time, nor for her to have spent a couple of hours nattering to NB. Was Mossop's even open on a Sunday night? So DL, AL, CV/KH, MH and NB cannot all be giving accurate accounts.