I think... and I'm going from memory here, that you can't just buy a battery harness with two way plug to go into the board. I think the battery harness is connected into a 4 way plug which also feeds into the trigger or solenoid or something like that. You can get these replacement harnesses no bother for a few quid or if someone at Dye / Proto is feeling generous, possibly nought.
If you intend to get a standard 9V battery harness and just snip the wires, and re-attached using solder, then RS sell these harnesses for silly money.
On a sympathetic note, I bought a used PM7 form the forums and it was sold as in good condition and proper working order being recently serviced for the sale. When it arrived I had to use a dental pick to get all the mud out of the screws in order to get it open, and it was clear it hadnt been looked at recently. To cap it off the eyes werent working. If I hadnt got it for a good price I would have gone mental. One friendly Dye Gun Tech later and a good clean and all was good. Sometimes it's easier to sort these things out yourself than messing around.
