£700 should get you an ev2 with a scope for hft, (second hand). Hft is cheaper to get into as well as the scopes for FT cost as much as a good rifle now. if you get your self a 2nd hand hand ev2 and then a hawk sr6 ret scope to go on top you will have your self a very nice set up to do hft.
Just dont get your self a Ar20 chances are you will be very disappointed with it.
Another rifles to look for would be: Air arms S400 Pros to this one is cheap to get hold of and you can all ways add to it later on if you wish ginb stock,rowen do triggers and palm rests,air strppers.
EV2 mk2 john Ostler reged - nikko diamond mk1