I have an early golf gti convertible and a VW LT35 campervan.
Problems arising with the LT35 with red kens ideas of keeping older diesels out of the area inside of the M25. (See dvla LEZ)
From 2010 (not to far off) it will cost me £100 or so a day! to travel to or from home in Bromley, Kent. My privately registered little used campervan will have to have around £2000 of engine exhaust mods or perhaps a change to petrol. I don't like the sound of the particulate filters and all of that as I hear of many problems. Perhaps a petrol engine from a car will drop in? I will bring this up in the right place. This looks to be a very good site, glad I have found it.

John