The following is an extract from an article in Flight International issue 11th Sept 1953 which covered the SBAC Show for that year.
Vickers-Supermarine Swift —The blue-painted Swift F.4 prototype, WK198, is Supermarine's representative at Farnborough, though an F.3 [sic] joined in the flying display on Monday. WK198 has two-position reheat for its Avon, provision for four 30 mm guns, and, of course, a radar gunsight.
Check your PMs Chuck_Joe.