Maybe you even find out that “Deep Purple” originally was to be called “Roman Purple” until Jon Lord was enjoined from using the name by a late Italian heir of Romulus Augustulus …
Apart from that, how about the Vanden Plas colours, maybe Morello Cherry http://www.barons-auctions.com/auction_details.php?aid=12&cid=90? I found a colour chart and Amethyst might also be your grail http://www.vandenplas.com/daimler/3379.htm.
Keep the faith
Jochen
75 XJ6L 4.2 auto (UK spec)
Black was definitely a series 1 option for the interior - I know because I own one Regency Red with Black interior. I would seem to be from factory as the kick panels are also black and match the early interiors (done in vinyl not carpet and also has no vent holes)
Its certainly not common I think I’ve seen a series 2 (in person) with a black interior as well. Most which appear black are in fact midnight blue.
I was under the impression that black paint wasn’t an option for the early cars - however this is based on Nigel Thorleys book which as we’ve already seen doesn’t quite give the full picture