Looking to buy a 6 to 7.5 t truck - need advice

Seen these?
climbingvan.co.uk/van-life/recl … rvan-dvla/
gov.uk/government/publicati … or-caravan
If you cant do that, then your vehicle will remain a truck wont it?
It is what is on the V5 that counts.

Also from
gov.uk/being-a-goods-vehicl … exemptions
“These types of vehicles are never exempt:
mobile exhibition vehicles
catering vehicles
mobile shops
mobile medical screening vehicles
vehicles with fixed equipment carrying goods not strictly for use in connection with that equipment, or towing a trailer that’s carrying goods”

Is a mobile workshop similar “type” to a screening vehicle? Special equipment fitted although no carrying of goods involved.

Roadside tug? If the V5 says goods vehicle, the onus is on you to prove you are exempt from O-Licence rules.

Do some more research before you buy anything. Try self.service@vosa.gov.uk or 0300 123 9000.
Maybe all will be fine, I hope it is, but I suggest don`t just take a punt.