Ah ... my father wanted to "do his bit" during WWII and, in 1941, volunteered for service with the Royal Navy. But, being an electrician by trade, and employed in munitions work with Barr & Stroud, Scientific Instrument Manufacturers (making periscopes, etc) was informed that his was a reserved occupation - as, indeed, had my maternal grandfather, a brass~finisher with Shanks' of Barrhead been told at the time of WWI, a quarter of a century earlier. There again, my paternal grandfather owned a joinery business in Kircudbrightshire, S.W. Scotland during the Great War and, at the age of forty + ...... was considered too old for active service, anyway.