I disagree and think you both have it a bit backwards in your thinking, they wouldn't work at SS as they couldn't handle the rigid shifts.
LMB provides a place for WGs to work who for whatever reason want very flexible start and end times to shifts. So flexible in fact they sometimes don't start their shift at all.
This increases the available pool of WGs working in Manchester parlours. This is why I like that all the parlours are different to each other, with different start times, end times, shift lengths, rules, leniency of rules, etc. It widens the kind of WG who can work in a parlour.
What isn't acceptable is unclear communication from LMB reception. If they say a WG is in the building and she isn't, then that is bad.
However, punters need to hold themselves accountable too. Don't book a flaky WG at the start of her shift, drive an hour to see her, then be upset when she no shows. Book her a few hours into her shift, call after her shift starts and ask "is she in the building as I don't want to travel if she isn't". I believe LMB has lied in the past in this situation, but I do wonder if punters are asking unclear questions, e.g. "is she working today" rather than "is she in the building" and then conflating the answers. Also, if you know the WG is flaky your questions should reflect that.
Also, some punters need to accept that some WGs are unsuitable for them because of their flakiness. There are other punters out there who can easily handle schedule changes, those WGs are suitable for them. So they still serve a purpose in the 'pool of WGs'. When saying this I am also specifically thinking of Phoebe's time at various parlours, who seems to attract a bunch of punters who ignore the crystal clear evidence that while she is a good WG (per reviews) she doesn't show to every shift she is put on website rotas for (also per reviews). I don't get why punters who are clearly time sensitive/poor or are upset by cancellations would try to book her. Read the reviews, plan accordingly.