Octavia Vrs 2.0 tfsi - stalling when warm

I've get a mysterious issue with my Octavia. It always starts fine from cold , however when the car is up to temp it starts to loose revs on idle or will often stall.

This makes it nerve wracking in traffic..

When the revs start to drop blipping the throttle makes little difference , then on occasion you start the engine again & all is fine.

As my car spends most of its time communing I took it for an Italian tune up to see if it made any difference , however it only provided a temporary solution.

The car has only ever been run on Shell v power nitro for the last 2 years since I have had it & there are no dash warning lights .

Any ideas what it could be , as it's driving me nuts as apart from one faulty coil a year ago the car had been great