The turntable is perfectly level. The AS weight has been removed and the lever rotated away from the arm. The arm has been rewired with Cardas and has a lot of slack hanging out the back. When working to align the cartridge, I did have to rotate it quite sharply clockwise so this may have created some unforseen force. I will check this as it may be the causative effect.
Thanks for the responses.
Thanks for the responses.