Progress Alert!!
It's been a while, back-burner probably doesn't quite cover it, but I finally got the electronics back together and in a working state. In case I missed writing it here, I managed to wire up my switch completely wrong which basically shorted out the battery, there was smoke and minor panic, after which I couldn't get anything out of it. Thinking about it now, it probably wasn't broken at all, but I'll get to that later.
I ordered a replacement main board and ended up with an RX14P (which came with it's own receiver board). I fitted it, I wired it up, I double and triple checked the circuit to avoid a repeat of my stupid short circuit mistake from before. Powered it up, heard a promising pop from the speaker, turned on the controller... then nothing. Nothing happened when I pushed the sticks. I checked it over, turned it off and on, tried again, still nothing. It wasn't until I tried pressing the three buttons on the controller that it suddenly sprang to life. It never occurred to me that I had to press the key button to start the tank, duh! I got the engine startup noise (at full volume, yikes!) and then tick-over, engine revs when I pushed the stick, machine gun noise and canon firing. Pleased is not the word!
It's at this point (actually while writing this post) that I realise my main board probably was not fried, I just hadn't pressed the start button. Oh well, at least this means that I probably have a spare working S&S board.
So that's pretty much where I am with things right now - I need to sort out my messy wiring loom and secure the battery in it's bay, then it's just little things like the odd stiff suspension arm and sorting out the engine cover that I lifted at the rear of the tank (it gives access to the on/off switch and charging socket, which I have moved and arranged so that I do not need to take the cover off. The underside is completely sealed).
I'll try and get some photos up here soonish.