Doing a google search of the phone number there are a series of different escorts - all in Leeds - using it and all calling themsevles "SKOOLIE".
Two things standout to that
1. It does seem like its either an agency or at least a pimp managing them all.
2. The Skoolie description for them all just feels sinister.
I would just trust Wayang's opinion that its a scam as he is good at this sort of stuff.
*Edit* Posted the above before seeing his angels comment