AP 1358, CHAP 1 Page 9 of 21 AL17
0117. Occasions when No 1 Service Dress may be worn. Officers on the Retired and Reserve Lists, Royal Auxiliary Air Force officers and ex officers who are permitted to retain their rank may wear uniform on the following occasions: a. When attending: (1) Investitures and Royal Garden Parties. (2) State ceremonial occasions. (3) Parades in an official capacity, in connection with the celebration of the Sovereign’s birthday. (4) Their own wedding or other military weddings when the sponsor requests the wearing of uniform. (5) When attending formal Service functions. b. When participating in an official capacity, in: (1) Non-Service parades. (2) War Memorial services and associated parades. c. When inspecting or visiting: (1) RAuxAF units in an official capacity. (2) Units of the Combined Cadet Force (CCF) of the Air Training Corps (ATC) on behalf of the Ministry of Defence or Territorial and Auxiliary Forces Associations. d. When appointed for service with the ATC (the rank badges to be worn are those appropriate to the ATC appointment). e. When on duty as officials duly appointed by the Ministry of Defence. f. When holding the appointments of ADC to Her Majesty’s Governor General or Governor. g. When holding the appointment of Lord Lieutenant or Deputy Lord Lieutenant of a county, High Sheriff or Sheriff and discharging the duties of that appointment. (Lieutenancy insignia may not be worn on RAF dress but entitled RAF flying badges may be worn on the Lieutenancy dress). Wearing the Uniform of Voluntary Organisations.
So Prince Andrew and Prince Harry could ,and in my opinion,should have worn uniform on the parades,because of their active service!
But I realise that the King’s decision is final! - Royal Politics!