ive matched a girl on tinder, been talking to a girl last few days and conversation has been flowing and has been good, but, she has replied with, "fair play" whats a good response to this to keep convo going?

Have you tried to arrange a meetup yet? If you've been chatting for a few days you should probs have already tried to meet her for a drink or something.
Also,

Derail. That story's retarded and it's nothing like that.