The Javelin was retired during 1965 and only one was left flying with the RAE until 1975, XH897 was used as a chase plane and a calibration platform for other new jets.

Not quite.

No. 228 OCU at Leuchars had Javelins on strength until, I believe, November 1966. They were training aircrews for the last 2 squadrons in the Far East, 60 & 64. No. 60 Sqn, the last unit to operate Jav’s, disbanded on 30 April 1968.