It sounds like the title of a Sherlock Holmes short story but in reality it's just an example of a bit of thrift in using up all those ends of masonry paint lurking in the shed.
You never know though. Could it be a secret dead letterbox for some admiralty plans or where photographs of RAF Lakenheath are hidden, those taken with a long lens of course? Or could there be men in long leather coats with blonde hair and wire rimmed spectacles in residence? I hope they don't go up to repair the flaunching on the chimney in those long coats, no they wouldn't would they, they'd be far to worried about snipers.
Watson, get the Bradshaw's Guide out, I think we could well be in Downham Market in just over two hours, and don't forget your service revolver.