Peterux & Mitchelkitman - Agreed about providing a measured response and I'm still working on mine.
I found this useful link.
https://www.smmt.co.uk/industry-topi...sions/testing/
Which should help defeat the DfT's claim that BIVA builders now have 25 years of 'modern' engines to pick from.
As the table shows that only a Euro 5 petrol engine (or newer) would pass Euro 6 standards and nothing other than a Euro 6 diesel engine could be used.
Cheers, Paul.