interesting comment from Cub, however I plan to raise the whole floor (including the base) as one piece. Raising the base should stop it from bending.
Cheers Chippy 
Chippy, welcome to the lovely after sales service from Cub. If it's any consolation, you are not alone.
Getting back to your floor suggestion. Are you aware at all, of what material the floor is constructed of, and the thickness of that material ?
I'd respectfully suggest you explore this issue well before trying to alter anything, as in my humble experience, the floor is ply wood and if it's any thicker then an eight of an inch, I reckon you'll be lucky.
On our Cub, they manufactured a frame resembling a roof rack which was cross bars across it, this stops the floor from twisting out of square, though does not stop it from cracking underfoot. That's why I caution any work before you establish how strong the flooring it'self is.