The RAF 8-day clock Mk IIC Ref: 6A/1104 - luminous, specification: G.420 could be used for Spitfire, Hurricane and other British planes. There should be stamped serial number below the "8 DAYS" inscription on the dial. The two last digits indicate the year the clock was made in. Is that 10406/42 or something like tha, for instance?
The clock of 1940 ...
View attachment 718542
the source: the net.