My experience with Thai places in Liverpool is that it is all a bit random. A girl could be a highly trained and experienced masseuse, but occasionally a random woman who happens to be Thai. Just a few of whom look a bit rough. The quality of premises can vary a lot too.
'Extras' on offer are a bit random too, varying between shops and particular girls. Which is not surprising, given that this side of the business tends to be a bit 'hush hush', whereas with normal WG or parlour, the menu and pricing are 'on the wall', so to speak.
If you know what you want, you can ask a specific question on here. Or try your luck and go in with an open mind, talk politely with the girl what can you do for her/what can she do for you.