In the UK, what is the process for the monarch to bestow honourary military appointments. For example, when HM Queen Elizabeth II made then Prince Charles an Admiral of the Fleet in 2012. Is it solely within the sovereign's gift? Is it done in consultation with government or the military?
Apart from a few honours in the "personal gift of the monarch" (such as membership of the Order of the Garter, or the Royal Victorian Order), all appointments made by the Monarch are done on the advice of, and in consultation with, Ministers.
However, this was unlikely to have been a particularly controversial decision. The position is entirely honourary. Charles never had any operational responsibilities as Admiral of the Fleet.