PT247, no sucking of eggs, matey, any help/advice is greatly appreciated, but yep, I tried the selector in all different positions. I'm using an 11.1 1450 Lipo, which I seem to recall is recommended ( not got the destructions to hand) AND remembered the bolt release each time I changed mags. From your earlier post, definitely not a blockage.
Straffham, I'll check the fuse if and when I can. BUT there is no way on gods green earth will I indulge in the dark and mysterious art of dismantling an airsoft gun. I WILL have some bits left over when I put the damn thing back together. Lol