What is the muzzle velocity of a ASI Paratrooper repeater Mk 2 air rifle or if I owned one would I need a license in the UK?

Im not sure about the first question, but yes u would need a licence for it if u wanted to stay legit.

,<<<<<new answer>>>>>>>

The model ASI Paratrooper and the Gamo Gamatic 85 are the same rifle. Just different name. The muzzle velocity is rated at 560 FPS.