Posted by Robert Hill on May 22, 2011 at 12:19:14 user eclrh.
I think the (worryingly named) Sunk light vessel is mentioned in WDM. It's certainly marked on the chart of approaches to Harwich that appears in the book.
A visit to this lightship featured towards the end of tonight's episode of the BBC2 series Britain's Secret Seas. It's now solar powered, automated and only visited for occasional maintenance.