Ian, I'm sorry to disillusion you - that is a first class scammer!
Anyone who is genuinely interested would OFFER to go to a cybercafé (even after a tough day of work - it is still peanuts by contrast!)
450 quid merely for a return flight is gaga!
Scammers have become more sophisticated and much more tricky than before.
Report her profile to the admins, they have superb and effective means verifying the person (including a "hard check")
I'll risk a wager that (s)he's a trickster.
I had such an encounter myself and ended up tracing her husband…
IF you still want to go on with her, ask her to go to a wifi caf. I bet she refuses. She'll find more excuses, than Swiss cheese has holes. Sorry sir, but that is my hard reckoning.