For what it's worth, SV Tech uprated my T28 T6 camper conversion to T30 but it was a fairly simple task as nothing needed to be done to the van. Apparently my existing T28 suspension was OK and the wheels and tyres had already been changed to a set of Devonports taken straight off a new T32. Suggest you talk to them about the art of the possible as it's not as simple as an individual just doing the work and then getting DVLA to issue an updated V5. SV Tech are an acknowledged engineering authority in such matters (but I understand that there are others out there) and they had to certificate that the vehicle was full up to spec for the additional load as well as providing a new silver 'weight plate' sticker that has to be displayed somewhere on the van where it can be easily read if needed (the old one under the bonnet is also left in place). Also, as somebody indicated above, there is a cost attached - mine cost £250 which was a discounted 'show price' at Malvern a couple of years ago and it was worth it to me. That said, I'm a moron when it comes to mechanical stuff and I therefore have no idea if it's likely to be a financially viable proposal (or even technically possible) to go from T28 to T32. Best of luck whatever you do.