Perusing Autotrader, can't find anything that fits.
Large saloon
RWD
Auto
200+ BHP
£10kish for sub 10yr 100k miles example
40+ mpg capable day to day
I think my choices are:
BMW 7 Series - too many reliability issues
…………
Remind me again why it would have to be a 7 Series, why not an F10 530d.
Apart from your budget dictating it being at the upper end of your vehicle age limit, all other criteria is satisfied.
Regarding the 7 Series, I guess it’s the luck of the draw. You may recall me posting some years back about my son’s friends 730Ld (Long wheelbase, hence the L). It was purchased from new as a private chauffeur car for airport runs as well as business use and he ran up galactic miles on it. The auto box was repaired/replaced at 265K miles and the last time I saw it the mileage was well over 400K miles.
No idea of any issues with it though.