Incidentally a VC!!!!!
There is a well recorded incident of a rather pompous Army officer who referred to a junior with the words........ ' and he won a tolerably good VC'
However, it is possible that Flash's relative was promoted to Rear Admiral so that he could undertake some work for the Admiralty, perhaps with a short period of uniformed service and the promotion was, therefore, effectively 'supernumerary' to the establishment of rear admirals. An example might be 'Extra Equerry to the King'
O-D