[David_Hayward (RIP)]

There's a nice pencil museum in Keswick, which is not far from my company's HQ in Appleby.

As regards the suggestion, I rather think that this is an amalgam of fact mixed with some mis-recollection? The existence and location of safe houses seems implausible as they would and did change all the time. Further, the cellular system was intended to prevent anyone outside the cell from revealing anything about another cell.