Since I posted this many years ago, the CWAAS have made the original article available online. This is comprehensive and includes other charts beyond the one below. Please go to the article, rather than using this page, which Iām only keeping for legacy reasons. See:
A personal non-commercial site. Main areas: Cumbrian Genealogy, Brighton & Hove pictures, Diary about growing cacti/succulents from seed, Comments on past present and future.