Well, I got an answer from The Beeb, courtesy of Steve Cram, of all people. The theme music was an instrumental version of “Invincible” by Carola. which was, I’m sure you’ll remember, Sweden’s entry in theis years’ Eurovision Song Contest. And, just in case you don’t remember it, here it is (removed as link is dead)
It’s hardly surprising to read that I also liked it at the time too.