To be honnest although they had some issues with my truck I can only blame myself as the items they had a problem with were the very things I read in the regulations and chose to ignore thinking they wouldn't worry about them! If you read through the reg's (which are pretty straight forward) and make sure that everything is as they want it to be (eg, Batt' isolator, second throttle return spring, some form of deflection for exhaust, Fire extiguisher as spec' etc etc) then you wont have any problem.
As for the soft roof, Someone at seven sisters did have mesh strapped to his cage which they seem'd O.K. with so do that if nothing else!