Thank you everyone for your responses. I never expected so many people to take an interest in my project. You have given me a lot of food for thought - hopefully using the information you have given me, I'll be able to track down my Grandfather's crew.
I know this is a long way off, but once the film is made (it'll be finished by April/May next year), I'd really appreciate it if you could circulate my film around forums, Facebook groups, friends and family - basically anyone who likes Documentaries or any aircraft enthusiasts you may know. I'm making this film not only so that I can finish my degree, but I would like the film to reach the audiences I intended for it to reach.
I will post on the forum as and when I know more or when I have an update.