Starting issues 2017 VRS Tdi (DSG)

hello all, can anyone help with this if you've had similar?

Back in May, my car started but was misfiring really badly. By the time it had registered in my head the engine ran fine and drove A1.

It now does this totally intermittently. Sometimes it will start then die, then I get "start engine manually", which I do but have to put a small amount of pressure on the accelerator so it holds revs which jump around 1000rpm and runs like crap.  After 10 seconds or less, it's level and totally fine. Drives great. 

It will (or won't) do it on cold mornings, or after the car has been sat for a couple of hours, or it won't do it for weeks on end regardless of if the weather is cold or warm, it's totally random. 

The car is fully serviced and has had a fuel filter change which was done properly so no air issues. 

It's been scanned numerous times and only has the intermittent code for the microswitch position on the DSG which I plan on sorting soon. 

I've fuelled up from reputable places like BP etc. I've currently got some injector cleaner in there just in case. 

Has anyone had this before?