[1] Mayhew was commissioned into the Royal Air Force on 28 July 1988 as an acting pilot officer.

[3] One of his main duties was to oversee the transfer of Leuchars, then an RAF station, to the British Army as a barracks; this was finalised in March 2015.

[9] Mayhew was appointed Knight Commander of the Order of the Bath (KCB) in the 2022 New Year Honours.

[10][11] In April 2022 Mayhew accepted the freedom of Causeway Coasts and Glens Borough, on behalf of the RAF, at a ceremony in Limavady, County Londonderry.

[12] Mayhew was criticised in an employment tribunal case in October 2023 in which he was found to have offered "hollow and unconvincing evidence" in a claim by a serving military officer.