I had a pre-puzzle guess at who would be the first to have a real crack at this one, and I was right! I'm sorry Allan, none of your guesses is correct. I'm having real regrets about this second part of the puzzle - my excellent source advises me that the image is copyrighted by the AMOC. One of this site's editors recently suggested that if anyone was particularly anxious about copyright they shouldn't allow the image on a public site, and it was therefore "fair game". All the same, I reckon it can only be solved by contacting the club, and that would open this site up to possible rebuke.
I'll leave it here for the time being, unless I hear from one of the editors. I have a copy of the programme for the meeting, which comprises an A5 sheet with the title of the meeting on the front, and a numbered list of entries on the back. Typical programme for those times of austerity. The puzzle photo shows some race numbers, and I can therefore "tie-up" those drivers, but the rest will be educated guesswork. A hint - they are all Aston Martins. (I have to confess, I'm no expert on AMs of that era, and they all look the same to me!)
According to Peter Swinger's book (which has been criticised for some inaccuracies), the circuit has had roughly the same format for some time until the recent major changes. His map for 1951 shows a shallow curve before the start/finish called Paddock Bend, which later became more convoluted as Russells. This would fit the curve seen in the background of the image. But that hangar had me for a long time, just like you. It must have been some demolition job - they used to hold B24s. The only hangars I can remember from the early 60s were the ones which housed Foulgers Transport on the left of the main entrance road. My dad used to park there to save the car park charge - Foulgers were customers of his.
STOP PRESS. I have just obtained the details I require - full info to complete the puzzle. I even know who took the photo. BTW the copyright isn't the AMOC's, but the Aston Martin Heritage Trust. Let's see how long this takes you all to solve.