All sorted. Ended up running 6 or 8 gauge cable through directly to pump. As my connector was melted, i managed to pull out one of the terminals easily and drill a hole, the other side was a bit harder but managed to drill a hole there also. Squeezed the cables through the holes, then filled up the socket with epoxy.
Got a plug off a mate, a 50amp Anderson plug, its fairly big and way overkill but will certainly do the job!