Hopefully the pic will show what has been done, for those that have Pmd me.
The chassis plate run back as far as i could get it, whilst still allowing for a change in spur and pinion etc.
The motor guard, which i run a fan on, has just had the thickness of the brass ground off. Holes in the brass plate allow the chassis screws to come through to the guard, in essence clamping it. The plate needed a slight whack with a hammer to get it to sit flat to the chassis. Two grooves at the back of the brass and just in front of the guard allow the saddles to be held securely. I have added a piece of 2mm black foam to damp the batteries and stop them rubbing (OCD i am afraid). The cut out side pods would take a further piece of foam should there be any sideways movement, although they really are held firmly.
Cheap mod, free in fact.
No need to faf about with carbon, making braces, etc etc.