Hi, of the three pistols that you have listed above the CP1 and Air force 1 are basically the same, however the SMK CP1 can be found for about £100 if you shop around.
The Gamo Compact has the best grip of all three mentioned, the grip does make quite a difference on a target pistol. In my opinion the CP1 or the Compact would serve you well starting out, try and handle both first, BUT if you find a Fwb 65 or an 80 at a price that suits you, go for it as the quality is superb and they last for ever.