I always thought that those SD1's were very unreliable, knew of a friend of a friend who had nothing but trouble with his back in the day, his close mates use to laugh due to seeing it on the back of a recovery truck more often than not,...I think he's had the 3.5 engine, not sure about the differences with this model.
That is what they always said - typical British bashing. I had 2 - the 2.6 straight 6 and the 3.5 V8 which is one of the finest engines ever made.