OK if your VW is as it came from the factory.
If you're "substantially" modified the 8 point rule looks like it will come into play.
What constitutes a VHI (Vehicle of Historical Interest)?
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/644732/impact-assessment-review-of-vehicles-of-historical-interest-road-worthiness-testing.pdf
To be considered as a VHI the vehicle must have been first registered over 40 years ago and the following
components need to be of a design of which would have been fitted to that vehicle at the time of its
manufacture.
• the original unmodified chassis or body shell (including any sub frames) or,
• a new chassis or monocoque bodyshell (including any subframes) of the same specification as the
original
• suspension (front and back)
• steering assembly
• all axles
• transmission
• engine
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/644962/vehicles-of-historical-interest-substantial-change-guidance.pdf
Criterion 1
If a vehicle has a power to weight ratio of more than 15% in excess of its original
design, unless such a modification took place before 1988.
As soon as you modify it from stock, i.e. changing the wheels to alloys and running "car" tyres, lowering, narrowing the beam, upgrading or changing the engine, etc, it's no longer a VHI, so no exemption from MOT or tax.
Tubs and chassis notches on your bus. That will lead you to a Q-plate and BIVA inspection.
Upgrade or change the stock engine and increase the power to weight ratio by 15 per cent or more. Sorry no more historical status.
A simple engine number check will reveal if your VW has a later, or bigger engine fitted.
I know, don't declare anything. The requirement to annually declare your vehicle's tax exempt status will mean that if you tell fibs you run the risk of at best the call for a BIVA inspection if you get pulled. Even if you have declared to your insurers all the changes you've made.
Feck....