Ananya Thai has a shop front at no. 91 (address is or has been available online). Don't know why anyone would need to phone them on arrival rather than just walk into the shop. Also cannot see why they would be watching where car parked and alerting guy in no. 73, rather than just getting on with making their money from massages & poss. extras. There may be some confusion with another girl who I think has been mentioned as working nearby, but apart from shopfront, similar comments apply.
There's an entrance to a flat very close to the location in question.The girls ask you to phone so they can run down, unlock the door and lead you up to the flat.