Nigel,
I have deleted the mi.mo file and tried to refresh the Home Page – the error messages have disappeared but I still don’t get the entire Home Page back – just the top menu and my original HTML block.
I was, indeed, following the blog suggestion you mention and I shall not attempt it again, but I’m at a loss to know how to recover. I have tried all the obvious things – have logged out, closed the browser, reopened, cleared the browser cache, logged in again, but can’t restore the original Home Page.
Any suggestions?