I may be wrong on this but MRT 308 isn't counted because as you say above, as I understand it, VW GB didn't order it (private order?) so in official VW dealer network terms it wasn't the first RHD car. That then begs the question what was and further more who owns the oldest UK RHD dealer VW in Britain?
This stuff is fascinating as it's historical to the UK VW movement.
55Kab wrote: