The association member researching the crew has now come up with this:
I intend to work down the list of the crew and have already found information on Walter Thomas Regan the pilot
The records show him as a Pilot Officer. He has the same service number as Flt Sgt Regan so he must have been commissioned at some stage. I will look further into this. I couldn’t initially find his birth and then found that strangely he may have been born in Germany in1923. His parents were Walter & Nora Regan of Barnsley. His Father was a Pelt Monger, a seller of animal hides. He also had a brother William Patrick Regan who was an AC 11 in The RAF Volunteer Reserve. He died in August 1943 when he was 18, seven months before his brother. He was not aircrew and is buried in a war grave in Barnsley Cemetery.