Dapol Pug problems

The below is an original run Dapol L&Y pug that was given to me in exchange for a days work in a model shop long, long ago. It's basically only been test run, but I had an idea to use it on Rhiw (I'll explain that later). On taking it out of the box I noticed that the footplate had split lengthwise

I can only assume this is plastic fatigue due to pressure from a self tapping screw. This screw goes through the motor mount and into the footplate holding the motor in mesh. I repaired the split with Daywat Poly and just to be safe put a thin strip of plasticard over the bufferbeam to bridge the fault as a belt and braces method. So far so good. The problem has now arisen that the motor mount 'flexes' backward toward the camera under use and drops the gear out of mesh. What it needs is something to secure it from the front as well as the self-tapper at the rear. Any ideas?