That was my very next move, St G! I was just reading the legal side of copyrighting on this website:
http://www.patent.gov.uk/copy/
It leaves no stone unturned and answers everything you need to ask.
Seems you are absolutely right about the law on this - there is no official register of copyrighted materials and we are left to our own devices to ensure that our work isn't plagiarised! In fact, we've already been doing the only thing we can to protect our stuff. Doesn't seem right, does it? I've been writing for years and have only just discovered that the posting/emailing system of copyrighting isn't legally written in stone, so panicked a bit. Still, I've been lucky so far and I hope you have too.
Oh well, back to the post office then! (and the emails..)
Take care
N