320d manual 2002 saloon remapped, full decat

i still have error code 4580 Rail Pressure Sensor - Plausibility -Pressure too High, according to the data on inpa my fuel pressure is too high in my fuel rail. I replaced the fuel rail, sensor and regulator with a second hand one from a 2007 320d. It improved it a bit, before the engine light came on as soon as i started the engine but now it only comes on when i drive it and it goes above 2000 revs as if when the turbo is kicking in. Due to my turbo packing in it has been replaced with a refurbished unit but this error remains.

so can anyone suggest what to check next, google searches reveal very little worth mentioning

so things been done -
checked fuel supply and return pipes for blockage, none found
replaced fuel filter
replaced fuel rail with sensor and regulator
replaced turbo (unrelated)