Flipping it onto it's back and removing some rubber matting I was presented with this:
|Rotten Chipboard at its best!
The was only one thing for it. It had to be removed, so out came the jigsaw and hand saw and below is where things currently stand.
|Most of the rotten chipboard is gone
I still have more wood to chop away from the left side, I think I will probably make a complete new base section and fix it onto what remains of the existing cab.