just an update ...... dropped the tyre pressure on the fronts to 36 psi. Needed to pop over to South Yorkshire, so that would be an 80 mile round trip and ideal for testing. I think overall there is a 10% to 15 % better feel to the car. It feels less loose, in particular in the straight ahead position. At speed there is more feel overall, but turning into side roads it still does not have the “Tarmac gripping” feel it used to have. On the fuel consumption increase, it does not seem that bad. I got 48 mpg, although i was stuck for several miles in the outside lane on the two lane section of the M18 doing 56 mph following lorries which would not pull in.
i will run with 36 psi for a month or so to get a better check on the economy.