Great links, Aidan.

Unfortunately, Coincraft haven't made an updated British catalogue for quite a few years, now (I notice there isn't one listed on their website). As I heard it, the prices in the last one were considered over-optimistic, so they're only now being considered a reliable guide.
Scoutjim, the Krauses cover Great Britain adequately enough for the period, but if you want information on the pre-1601 "English hammered" series, you need one of the British books.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis