You were right, I took it all out and there was some gunk in the left hand side which stopped the cup screwing in after 50Nm. I did it manually with a wrench a few times to clean it up and it went in easy after that - completely flush. Thanks for your advice! :-)
You were right, I took it all out and there was some gunk in the left hand side which stopped the cup screwing in after 50Nm. I did it manually with a wrench a few times to clean it up and it went in easy after that - completely flush. Thanks for your advice! :-)