I made another list, which I headed 'Guessed', but I was just as sure of the one as the other.
GUESSED (1) Place not harbour but open coast.
(2) Boat small--trawler, yacht, or launch.
(3) Place somewhere on East Coast between Cromer and Dover.
It struck me as odd that I should be sitting at that desk with a Cabinet Minister, a Field-Marshal, two high Government officials, and a French General watching me, while from the scribble of a dead man I was trying to drag a secret which meant life or death for us.
Sir Walter had joined us, and presently MacGillivray arrived.

He had sent out instructions to watch the ports and railway stations for the three men whom I had described to Sir Walter.

Not that he or anybody else thought that that would do much good.
'Here's the most I can make of it,' I said.

'We have got to find a place where there are several staircases down to the beach, one of which has thirty-nine steps.

I think it's a piece of open coast with biggish cliffs, somewhere between the Wash and the Channel.