Thanks for the answers guys will have a go when I get in. It sounds like I just wasn't dainty enough when I swiveled the projector if we're talking mm making a difference. It's a great relief it's human error and not the pj - I just need to be a bit more patient
Apologies to Croc for the appalling use of English. When I said it made no difference I meant it didn't solve the problem.
In my defence, it was a long weekend of mounting my screen, which arrived with a dent to the casing that I finally decided I could live with, only to find that it won't retract back up once it was on the wall, so it looks like it'll have to go back anyway.
Then it was a case of moving the pj into the new position and of course, moving the DVD player, Sky+ box, video recorder, AV receiver and speakers, only to find I couldn't get a square picture.
And all the while getting shouted at by my daughter to leave it alone as it was fine and she wanted to watch a film - during which I spent the entire time looking at the black borders because I was irritated by the leakage in the bottom right corner and the slant of the picture
Thanks again,
Horace