I spoke with chassis developments, the guy said that although the mk6 Transit can be worked at 4.25ton and there are a lot of them out there,the only persons allowed to have the truck at this weight was government departments.
Police, Ambulance and Local authority, I presume that Ford designed the twin wheeler to go to 4.25 ton with say a 16 seat minibus with 16 well fed coppers an all their riot gear, but the police would not want to fall foul of VOSA's weight limits.
Same goes for the Ambulance service, with all the equipment they carry and a tail lift.
It would seem that Fords did not want to incurr the fitting of tachographs as standard across the fleet of MK6 3500gvw (4.25 ton) therby saving lots of money.
Chassis developments said that it could not be uprated, VOSA are no help.
So I won't be carrying any S class merc's anytime soon.