OK, think I've fixed it!

My first error with the 403 was caused by AdminTools not allowing site templates. I deleted the itemform.php as Fotis suggested but as it never cleared the error I recreated it.

When the 403 error was sorted I should have done the same with itemform.php as that would have cleared the Error0 error.

Thanks Fotis, I did see an earlier post from a few months ago where you suggested the itemform solution which was what encouraged me to try again.

Thanks!