Nice car Alexander. There was a time when they couldn't get enough of these in Japan and the values of UK cars went through the roof.
I remember from my time in Rover Cars that there were an number of extended wheelbase Rover 800s which the factory badged as Vanden Plas. they were very nicely done to with a subtly extended rear doors rather than adding in a gusset (that word again). I also recall that the Vanden Plas name was used on the first generation of the aluminium Jaguar XJs when sold as the top derivative in the USA - badged engineering indeed.
the photography for this article was hard work, but turned out very nice. And I was very pleased with the article - nothing about me on there, but a rather accurate history of this particular ADO16 variation. It was in fact quite a bit better than expected. Now only the landcrab has not had a feature here in Germany (ADO16, Maxi and 3 litre have been done during the last 2 years). I'm working on it