Ive been very silly! After checking your first post I had switched them over to A1,2,3 and 4! So obviously when you sent me the new one it had the same problem.
That has stopped the strange noises, however there is a very long release on the notes if you play a few after eachother. Ive changed the delay time down to 10 which seems to help but its still playing a note for ages!
Sorry to be a pain, Im just not so good on velocity!