Many thanks for your reply, Len.
Since writing my message I have dug out an old chart which Tom Kermen had from an IoM researcher some 25 years ago. She mainly followed his line of William Kermeens, and said that a lot was guesswork, but interestingly she gives the Ann you noted b.1806, the daughter of Wm Kermeen and Margaret Davies, as marrying John Kermeen [but gives no descendants]. William's parents were William [1743-1813], and Isabel Craine of Ballig, Lonan. Son William's brother Edward married Ann Carroon and they too had a daughter Ann b.1803. Another branch of 'The Corony' Maughold family has William 1775-1840 and Jane Looney's four children as Isabel [b.1804], Catherine, William [b.1808] - and Anne!
Sue