Hi Migsy, I'm the 'very pleasant chap' that told you about the lead weights in the bulkhead!
After seeing your car at Cobra and seeing Atomic Carbon's new car, I was inspired to take the dremel to my CR.
Armed with only a small sheet of alloy and a sheet of nylon style plastic I created this:
It's still a work in progress and I haven't run it yet, but I put the alloy plate from the two gearbox screws all the way to the front of the battery slot. It was left wide so that the 4 battery posts would screw through it and the chassis holdong them together. Another alloy plate forms the battery retainer and I've used some brass tube to form a brace between the top of the gearbox and the battery. It seems pretty rigid, but once I'm happy I may bond the alloy to the chassis.
I also managed to reverse the motor plate, took a few goes but I've managed to do it without modifying the gearbox (other than two holes) or the layshaft. When I next strip it down I'll post some pictures on how I did it.
Hopefully see you at Cobra soon.
Pete