I know I have posted this question before but the problem is reoccurring and whilst thankfully it was fixed by a forum member I don't know how but did ask on the discussion. Thus as I edit the part the problem comes back and I don't know how to fix it.
On this file there is a gap on the pivot point. I have made the sketch for the curve coincident with the part which is why I don't understand where the gap comes from. Obviously this causes a problem when trying to fillet the parts sharp edges.
(You may need to rollback the part to before the last mirror to look at the problem properly)
I'm still learning the software and am aware that there are such things as dumb questions so I apologise if this is one.