Many thanks to both of you for your help. At this rate, I'll be needing a lorry to take my books to the post office tomorrow! (Not that I mind, I need the space!)
Sophie's right - I live in the UK and have sent a fair amount of books to the US or Canada using the Surface Mail option and some of them have arrived in less than a fortnight! I generally sent airmail for anything going to Europe and for small books going to the rest of the world - sometimes the difference between surface and airmail is only around 50p - but larger books go by surface mail. So far, no one's complained! Just stick a notice in your status message so that people know in advance.
