Hi all. Really sorry I forgot to post. This is how it went with Audi, Oldham.
The technician told me that the diagnostic found no faults and that the issue was that I had deselected intelligent coasting in the MMI. He told me that he activated it again, drove up and down the motorway, and all is well. So…when I went to collect the car, and although I told him that the intelligent coasting mode had been switched off since new, he was adamant that this is what the issue was.
Anyway, since being plugged in the diagnostic, and intelligent coasting off again, it’s back to normal !?
I think a reset of the ‘brain’ of the car must have been done, but I wasn’t told that.
in conclusion, when the electric charge is depleted, it shuts off the petrol engine into regen electric just as it should. The complete opposite to the issue I had, which was that the car never shut off the petrol engine, and instead decided to charge the battery, which resulted in sub 20 mpg for two weeks of driving.
Again, sorry for this very late post and that I can’t be more helpful.
Andrew