A quick update of progress...
I have been in contact with the Dellow register and they do indeed have a DVD of the race! A copy is on its way to me as I write. By all accounts it has quite a lot of footage of the winner receiving his laurels (literally) as well as some action shots too.
The Dellow Register had some contact with Doug Steene who came second in the 1955 race driving a Mercedes 190SL but won in 1956. A replica of this Merc has been built and this year it was raced at Shelsley Walsh by Doug. Maybe some of you saw the car..?
Bob Ritchie raced out of Hong Kong and I am currently in correspondence with some sports car clubs in HK which are now engaged in the hunt for the Austin Healey itself.
I am enjoying this.