Ive done 100k miles from new.
All I know the test was done at the crank.....as a guide an RCF was also tested on the same day also at the crank and it produced 460 BHP, ok this was only 1 year old so i would expect it to be close to its original claim, but the point is its the same same test and huge difference.
I actually used Surrey Rolling Roads in Farnborough (who was recommended to me by a Lexus mechanic).
So have you guys had a BHP test?