Try our re-instated info resource - "Aladdin's Cave" (Main menu)- sorry it's taken so long to fix
Dom, the top right hand lug is the culprit. The top of the lug bracket should run parallel with the top of the frame, thus giving you the 15-20mm of misalignment you are experiencing. I appreciate that no two welds are the same, but yours has been re-welded imho. If other members could provide a photo of their their bracket positions this will become immediately obvious. That’s a bugger🤨