OK, thanks for the response - and from Mr Calibre himself no less
I had hoped that it was me just doing something wrong in Calibre, but good to know that it isn't user error!! I don't have the original epub, and I don't understand HTML, so I'll just live with this. It's not a major problem, just an annoyance.
Thank you very much for your reply.
P.S. I'm new to this whole ebook thing, but I'm loving Calibre - it certainly makes it much easier to manager my Kindle