They will have one of those girls' records for other reasons.
I would be very surprised if Prestwich was council owned.
They certainly have the money to, they're bloody loaded, Sandy and her husband own a mansion in Cheshire and Merv owns a small plane. Wouldn't be surprised to see a several million pound POCA figure.
You need to correct that to "part owns a small plane". If you know where to look, you can even get the registration details of the plane.
You'd be right about the Prestwich branch not being council owned. Again, if you know how to do a back search, you'll even be lucky enough to find out who the letting agents are (or else you can get full ownership details for a mere £3 via the Land Registry).
Bringing in an American legal beagle is going to do them a fat load of good unless he is, first, allowed to practise in the UK, and second, knowledgeable about English criminal law. One interesting thing with Brexit that will have a bearing on this case is that once the trial takes place, along with any probable appeals, the UK will be out of the EU, in which case any possible appeals to the ECJ will be impossible (although they may still attempt to go to the European Court of Human Rights).
If the cops want the details of all the staff, they'll have no problem with this, as it is fairly common knowledge that Sandy, like a number of other parlour owners, kept records of the staff when she took them on (eg passports).
What I'd be wondering about is how many guys are now on the records of the cops as known punters. Every guy who was a Sandys member may have simply given them a false name when enrolling, but that name would be on the database of clients and who has seen which WG on what date. Tie that up with possible phone calls received on a certain date, not to mention credit card details and recorded images on the CCTV for who knows how many weeks before the raid occurred, and you are onto a tasty list of punting mugs numbering into the hundreds, if not thousands.