Thank you. I know a bit more, but my troubles are not over yet.
I discovered early on that one had to have a personal account before creating a business page. So I set one up in my own name but using a business e-mail address. I'm not now sure how to access that personal account (I'm not even entirely convinced it exists independently of the business page) - whenever I login I arrive at the business page.
A few days ago I set up a truly personal account using my own name (as before) but this time my own e-mail address. When (after my last post here) I tried to register that account for building an App, FB came up and said permission was refused because I'd used a false name (or words to that effect). I suspect this is because there are now two FB accounts with my name on them, with different e-mail addresses, but there doesn't seem to be an obvious way of verifying this or sorting it out. I have had to scan my passport and send it to FB as part of their 'appeals' procedure. I await their mercy. Meanwhile I'm not locked out of either account, I just can't operate them properly.