Key for RAF Mk 1 aircraft clock (6A/433)

I have been trying to locate the ref number for the key used in the RAF Mk 1 Aircraft clock. The clock is described as follows:

“This clock is for general use of a crew in a cabin on a flying-boat. It has an 8-day movement and is key wound from the front.”

This clock was in service in the early 30’s and into the 50’s.

The clock features in AP1275, the RAF Instruments manual in the following editions:

April 1938
July 1946
March 1949
June 1952

Gone January 1953

When I look in the stores book, AP1086 (December 1945) no keys are listed as an accessory for this clock.

There is a key listed for compass correctors, 6A/365; described as; Keys, No.1

Is it possible that this key is what was used? Is anyone able to shed any light on this mystery?