Sav you are a star by just replying. I went out to check the geometry and noticed that one of the bolts through the gate hinge was fouling the arm. Hacksawed the thread off by 2-3 mm and it is perfect.
It was literally touching so I expect that the brackets when done up have settled and moved ever so slightly which caused the issue.
It was literally touching so I expect that the brackets when done up have settled and moved ever so slightly which caused the issue.