... er ... Thanks for all your thoughts. I didn't say it was a blue box - it was box-free when I got to handle it. It did have the blue tartan backs so beloved (or behated) by so many of us. It was very worn, and when I handled it it felt as though it had been through a few sets of hands (its owner told me she picked it up without the box in a second hand shop). First think I looked for, in the absence of a box, was th copyright marker, and when I didn't find it, I high-tailed it right over here.
So thanks again.
When I meet up with her again, I'll check to see what colour the World's sash is, and whether the Magician's skin has that pre-cancerous look <grin>.