Well it has been nearly a week since I drove away from Peter's with a smile on my face. I still have one!
There have been no technical issues at all ,if not for the increased performance there would be no way of telling.
I have done about a 150 miles at the end of a 580 mile tankful so changes in the mpg are minimal. The big differences that I have noticed is the increased performance at low throttle inputs, the car is just "friskier" probably 10-15%.Another is in the city or hilly driving (I live on the Pennines) the overall mpg drops slower. It is still very early days and it will be interesting to see results over a tankful of petrol
All in all I am more than satisfied cf. to my 11yr.old battery.