I was going to say that £90 for a massage with a happy ending was expensive then realised I've paid £100 for an hours tantric massage before - d'oh! A tantric massage can be awesome so let us know how you get on and whether it's any good.
I'm a little put off by her doing outcalls - when I've been for tantric its always been visiting the girl where she has the room set up right and a proper massage table, mood music, etc., you're never going to get the full tantric experience if she's just rubbing herself against you on your bed (although I expect that would be pleasing...)