I had a tiny pinprick in the vacuum line going to the ECU.
the hole was getting partially covered and uncovered and the vacuum was going all over the place on acceleration (i have a vacuum gauge) so the car would chug when pulling away and accelerate as normal then suddenly judder without me changing throttle position.
i reset the ECU after changing the line and have not had a chance to drive very far since as i only did it a few hours ago, so i will report on whether the settings return to how they should (before the problems) but when i did drive it it was much improved and far more enjoyable (and sounds better) these lines are one of the first things you should check when you experience a fuel injection fault and in this case they have been found to be the problem (or at least one of the problems) I have also recently changed the fuel filter and fitted a genuine bosch oxygen sensor, so that cant have done any harm either!
The new vacuum line only cost 20p!!! and i made sure i got the right thickness and diameter. So in this case it has cost mere pennies to fix. Fingers crossed that my mini will behave itself from now on and that it was the only problem causing the symptoms
