I was hoping that either 'LATHE' or 'LETHE' would be an UK island, but sadly it appears not. I have tried all the Scottish islands (and yes, before you say anything, I have a book which has details of all 162 of them which are over 40 hectares) and the only one which gets close is BERNERAY. I don't do foreign languages but SWMBO has a French dictionary which says that 'BERNER' means half-mast. I'm not sure how 'AY' connects to that.
If you think I'm rambling, it's probably because I've been working in the garden for most of the day and it's been 25C. The best cure for that is half a bottle of good Cabernet.