RNZAF Timer?
An interesting piece but I am not convinced that it has much to do with the RNZAF. Anything acqured prior to the mid 1970s would have been marked with a 'pheon' ie the Government broad arrow; after that it would have had a NATO stock number (NSN) or at least a partial part number. It is unlikely to be a camera timer (too imprecise; normally cameras are timed using a much more sophisticated intervalometer). I haven't dealt with ordnance, but imho I don't believe that it is a bomb timer (which are normally a count-down timers, and rarely display a clock face).
Can't account for the RNZAF markings - they look relatively fresh compared with the outside of the case, and also the inside - the mechanism has been worked on quite a bit.
CC