Chris Aviation, superb diorama of the Sepecat Jaguar T2 XX830 (Raspberry Ripple) Empire Test Pilots School M.O.D. Boscombe Down. Test flying revealed that a significant number of changes were necessary, and production airframes would add both ventral fins and an enlarged tail fin to improve stability - this was quite an issue at the time, and a lateral auto stabilizer system had to be added too.
This is partial text from the full article (usually with photos) at https://aeroscale.net/news/jaguar-t2-xx-830-empire-test-pilots-school-m-o-d--boscombe-down