I helped out an embassy member in Saudi who had a terrible noise from the engine of his SD1. It was only that a water pump bolt had backed out and was contacting the pulley, but terrible noise.
It had electrical problems in that the tailgate lock would just keep chattering away.
I drove it around the block and was very impressed by the flat handling.
On P6Bs, did anyone notice on the Jack Irish season 3 episode 2? that they destroyed a good P6B by backing it at speed into a pole. Bit of a waste but I guess cheaper than a Studebaker Hawk to crash.
BTW they produced SD1s in India for many years until maybe 20 years ago and AFAIK they were fitted with a Vanguard engine. I have seen one.
Regards PhilipA

Standard 2000 - the Rover SD1 redeveloped for India (aronline.co.uk)