First off, its all working fine now, no flowing of the fuse anymore, air going is and out, starting fine, so its all ok now and seems to be all sorted,
the fist thing I noticed taking the old pump off was the the front was lose on it, 3 hex screws where the cover plate is for the piston, so for a start of that's lose the air is going to escape, ( its filthy inside now as well) so I checked the new one, and its the same not lose, but needed 3 more turns of the hex for it to seal correctly all the way, now this has no bearing probably on what was happening to me and the flowing of the fuse, so I took the top off where the brushes are, pulled the whole thing apart, and undid the 2 screws even holding it so I could look at the underside, and game it a good sniff for electrical burning, nothing and no dray solder joints, wires seemed OK, so I don't know what it was, it looks a little greasy but that's all