Simply return it to AJP.
I know that Antony prides himself on customer satisfaction.
He would not quibble just simply replace the part with a new one or return your money.
The best way to resolve the fitting issue is to let him have the rifle then the part can be machined to fit precisely.
I've had several items made and always been satisfied.
I didn't go to Norway to look at rocks & water youth, I went to shoot.
Avoid Welsh Paparazzi