Mostly one day a week I visit Bury, because GFE and LM are literally around the corner from each other, that is a big selection of wg's if you haven't made an appointment.
LM always seems to have a reasonable selection if you visit during the afternoon and haven't booked. That's what I have found anyway.
GFE is great, but can be a bit up and down depending on which day you visit, in terms of the best looking women.
I tend to book before I go to Sandys, as I have usually seen/selected the wg the week before. The best wg's can get busy, on certain days, especially if they are new, good looking or have an excellent reputation.
You can just roll up to any of these parlours, without being a member, and strike it really lucky, with some of the best wg's available because it happens to be a non busy period.