Thank you for the kind comments.
Tonight's success was with the Motion Control Module.
This is how it arrived home, fused into a mess of parts, cardboard, melted plastic etc.
These pics show it once I had removed it and broken off all the stuff stuck to it.
You can see a clean green area on the the PCB. This is where something had snagged around one of the surface mounted capacitors, which was then pulled from the board as I was untangling it. Fortunately, it stayed in the case. You can see it in the upper right hand corner of the PCB, near the first spade connector.
And these pics show it as it is now.
I have blurred the chips and relays to prevent any industrial espionage.
Unfortunately, during the cleaning process, and I had to be quite vigorous at times, one of the legs of one of the MOSFETs broke. When I did the first power up test, everything looked OK, but when I tried it with a motor, that side failed due to the current overstretching the other MOSFET. Fortunately, the built-in current sensing circuit kicked in exactly as designed and prevented any cascading damage to the board.
I ordered four replacement MOSFETs, soldered them in tonight, and have tested both sides with a motor and both sides now work perfectly.
Adrian.