After 11 weeks 4 recon injectors, Glow plugs, EGR valve, and hours of electrical testing. First garage admitted they didn't know what to do.
So car still in limp mode showing p0263 code. Went to another garage who specialise in VW Audi Skoda.
After trying to update/flash ECU he suspected this was the fault.
He fit a used ECU with the same part number and programmed and coded it to the car.
Car now is now fixed no limp mode or fault codes.
Hope this helps. I can pass on garage details if anyone needs them. I'm in Pendle area of Lancashire.