New check valve now fitted. The ribbed pipe ID was about 14mm and check valve OD was 13mm. Wrapped self amalgamating tape around the valve and gently pushed into the the cut pipe.
Secured with worm drive clamps.
Took car for a spin, seemed better down changing, on part throttle while in tip mode.
Will take a few Vagcom plots of boost Verse RPM when I've a chance later in the week to compare with previous reults.