Well, bought all the bits from TPS, including the service items and decided to tackle that first in case this was a cause of the issue I was seeing
After a bit of a sketchy moment on the axle stands I got the engine and DSG oil and filters changed, along with spark plugs, air filter, fuel filter and pollen filter.
That appears to have cured the issue, car feels totally different and the P0011 has stayed at bay - I guess the oil was just old and thin.
I am planning on doing the belt and chain still, but will leave it until a little later as it’s been a busy few days. Also going to get a VIS balance shaft delete kit as I’ve heard they can be a problem.
I also did the DSG basic settings/adaptation which I’d not done before - car feels so much smoother and the clutch is much snappier where before it used to hang on a lot in second mainly.