AAC Dauphin at Brize Norton 21/10/21

[Hunter 02]

Did anyone note the registration and callsign of the blue AAC Dauphin (ZJ78x) that was conducting low approaches at RAF Brize Norton on 21/10?

I noted it once whilst at RAF Fairford travelling westbound from the Brize Norton area at about 12:40
I also photographed it twice at Brize Norton between 14:00 and 14:30 (presuming this as being the same one)

Any help would be greatly appreciated.

[JAWS]

MAR 11/21 has the callsign as "Hammer 13" with 658 Sq