I bought this book to prepare for the Yachmaster Shorebased Course; I took delivery just before I joined the course. I didn't realise at the time that my course fee included a study pack, which included this book. The one in the study pack had a different coloured cover, which prompted me to check the publication dates - study pack 2009 Edition, Amazon 2002 Edition... I haven't been able to find any differences in the content (doesn't mean there aren't any); however, the Amazon supplied item is clearly old stock and, although cheaper than the RYA supplied latest edition, there is no mention on the website that it is out of date.
That said, any changes to content are not obvious and if you can live with a not-quite-up-to-date edition the book is still very good and Amazon sell it at a good discount.