I had some success over the missing blurb in Amazon.co.uk. I got an email back from them, and they're attributing it to 'a temporary problem in our database' which they're apparently sorting out. It wasn't only myself that was affected; so were a couple of other Tor UK authors.
They also sent this link, www.amazon.co.uk/add-content-books, which you can use to actually enter the book's details yourself (as opposed to just dumping it online via the 'reviews' option). Useful, particularly if you're, say, a small publisher. There are, as you'd expect, plenty of warnings about precisely where your information is going to go if they have any reason you're a)not really the author, or b)not the publisher.
So I'll give it a couple of days, and see if anything appears. If you end up duplicating the information - ie you manually post something and then their database repeats that information, which can apparently happen - they'll sort it on request. Nice.