Who are the officers and/or what are their ranks.

This is a photo of my wife’s grandfather from WW2. He is the man on the left in the black coat. He was a captured German solider turned translator. This picture has been floating around the family for a while and no one seems to know anything about it. The officer in the middle looks important. Any help identifying the officers and their ranks would help me out.

Thanks

Trying to think on the identity of the officer, but that will take me a long time, so be patient.

However, the venue of the photograph make me think Bletchely Park.
I Respectfully suggest you may wish to begin your researches there, and perhaps further extend them into the “Y” service of British Army Signals (Counterintelligence is what it becomes). Next step up the research ladder is the difficult one: GCSC Government Communications School of Cryptography. As that is an ongoing unit to this very day, almost anything of its’ history is very deliberately obscured by law.

I wish you every success.

Respectful Regards, Uyraell.