N1 class does not govern speed limits alone.
I believe a VW Kombi is classed as a dual purpose vehicle for speed limit purposes, not the reduced commercial limits, due to the rear seating and windows and unladen weight below 2-tonnes.
From. Gov.uk
Vans, car-derived vans and dual-purpose vehicles
Most vans:
- have a lower speed limit than cars
- must follow the speed limits for goods vehicles of the same weight
Vehicles under 2 tonnes laden (loaded) weight may qualify as a
‘car-derived van’ or ‘dual-purpose vehicle’. These vehicles have the same speed limits as cars.
A dual purpose vehicle is a vehicle constructed or adapted for the carriage both of passengers and of goods and designed to weigh no more than 2,040 kg when unladen, and is either:
- constructed or adapted so that the driving power of the engine is, or can be selected to be, transmitted to all wheels of the vehicle
or
- permanently fitted with a rigid roof, at least one row of transverse passenger seats to the rear of the driver’s seat and will have side and rear windows - there must also be a minimum ratio between the size of passenger and stowage areas