As near as I can figure, the British Admiralty has ENC charts available. See <http://www.ukho.gov.uk/amd/costs.asp#ENCsp>. Seems as though there's some sort of subscription service required, though.
Otherwise, Bellingham Charts has electronic charts for many different brands of plotters. Pricey, of course. <http://www.tidesend.com/index.lasso?page=echarts_region>