I had a Nissan Navarra (or whatever the crewcabbed pickup is they do) booked in for first MOT a couple of weeks ago. The gross weight put it into the dual purpose vehicle category (3210 kg IIRC) BUT how the heck do I know the unladen weight of it? I'm guessing it would be stated on the log book which wasn't presented at the time?? Assuming a payload of around 1000 kg this would be over the weight stated in the manual so we didn't test it, apart from that it was the size of a small county anyway and would probably have been too big for the ramp.
If it's a 'pick up' and can carry goods & between 3501 & 3500 kg gross then it would be class VII - unless you could confirm the under 2040 kg unladen weight