Since the 1970s, three companies have produced chronographs for the Royal Navy and the Royal Air Force: CWC (like our lot), Hamilton, Precista.
These chronographs are distinguished by their asymmetric cases, designed larger on the right side to protect the crown and buttons, in this example we find on the case back the stamp 0552, to indicate the property of the Royal Navy.
The dials, like those of other military chronographs of the time, are essential to facilitate readability. In addition, on them, there are the Broad Arrow (an arrow) and a circled T, the first identifies the watch as property of the British Crown while the second indicates the presence of tritium.