This question has cropped up from time to time in past years and has never yet, to my knowledge, produced an accurate answer to it! May I suggest some extra sources that may be of help..

Assuming, respectfully, you’re certain that the photo was taken at Hursley (more on that later) have you Googled SUPERMARINERS ? 

https://supermariners.wordpress.com/about/contact/ .

Maybe they have an original copy of it? They have excellent lists of who was working at the many Southampton and Salisbury area Supermarine sites, as well as a wealth of other information on the company and staff.

The pilot standing on the left of the photo is not Jeffrey Quill. Is it Mike Lithgow? He had retired from the Fleet Air Arm and joined Supermarine as a test pilot in January 1946 and became the company’s chief test pilot two years later. He would have extensive knowledge of Naval aviation matters and thus in a good position critically consider the Seafang for the Admiralty. Indeed in September 1946 he flew a Seafang in the high speed air racing event at Lympne! Guy Morgan maybe?

Taking another direction, no photographic accreditation or copyright holder has emerged (so far) to help. The image to me always has a gritty feel to it and seems to be possibly an amateur not an ‘in house’ photo by the company photographer (C.Douglas Burr) of the time. Or maybe it is simply a copy of a copy! Where was it constructed? Quite possibly Hursley Park house, then trucked to maybe Eastleigh, High Post near Boscombe Down, Worthy Down, Chilbolton. Probably not Chattis Hill, there were other sites that were also used in Wiltshire.

Supermarine’s archives were held at a Cambridge University library for many years. I was told recently that they were moved to BAE Systems Central Archives at Farnborough, Hampshire. I haven’t searched there as yet, myself.

There is a helpful website relating to Chilbolton by a local history group it details Supermarine’s time there;-

https://www.wherwellhistory.com/topics/places/chilbolton-airfield/chilbolton-airfield-chronology-of-dates

I have an old friend to ask if he knows the answer to this and if there’s any answer I will respond here.

Good luck in hunting this one down, will you keep us in touch with progress, please?