Cheers guys, sound advice and opinions all round.

Hustler25: Good point about not wanting to f*** things up with good mates, i have a similar stance on that but shes a friend who i rarely see tbh and i dont even know most of her mates. We talk pretty comfortably and always have a natter when we see each other, one of those people you always give 5mins of your time to if you see them around, and i see her so infrequently that i might as well go for it. Shes nice, hot and intelligent (blonde too ). But sounds like a good idea, the "how are you gonna repay me" question could provide me with a marker to work from.
Summer Junky: I do see her, but only rarely, out and about, maybe in the gym or around town (she lives about 100m away from me). Gonna throw a masterful text (sorry dolphin!!) her way, a solid text can go a long way and shows calmness i think. Will let you guys know how it develops though.