Watch List notes:

Commemorative Medals, Neville Chamberlain (1869-1940; Prime Minister 1937-1940), "Peace in our Time", uniface Bronze Medal, 1938, by V. Demanet, head left, PAX in field before face, the blank reverse engraved with facsimile signature and "10 DOWNING STREET 9 – 2 – 39", 70mm (BHM 4388; Eimer ), extremely fine
The 9th February does not seem to have been a special day at 10 Downing Street and the cataloguers cannot account for the engraved reverse.
Victor Joseph Ghislain Demanet (1895-1964), Belgian sculptor and medallist