I'm not a Legal expert but WHY?
All VW have to do before you finalise the purchase is to inform you of a change in the Advertised MPG and CO2/N2O figures and ask if you are prepared to accept this change. If the Answer is NO then you get your Deposit back. If the Answer is YES then you get title to the vehicle and that is that.
The ONLY people who, In my Opinion are entitled to compensation are those you had a Guaranteed Delivery Date which has been delayed due to this Problem. How many had a Guaranteed Delivery Date in writing? Very few I bet.
Another group who could be in line for Compensation are those already in procession of a T6 bought with the originally specified MPG and Emissions who now see their vehicles re-categorised - Maybe.
Another question. What if it had gone the other way - Improved MPG and Emissions. Would those awaiting delivery be happy and be prepared to pay More for their cleaner vehicles? I doubt it.
And lastly, Hand on Heart, how many buyers would admit that MPG and Emissions was a deciding factor in their purchase of a VW California?
Over the lifetime of my vehicle I will spend an extra £1000 on fuel and generate 10% more pollution. That is worthy of some consideration in my books
Possibly True, but consideration by YOU not VW. If you say NO then these non-registered vehicles will go onto the forecourt at full price. VW will not lose out in the longterm looking at the lead times for new orders.