Any ex-LW adviser for 1969 BofB film?

[tcolvin]

I idly watched a bit of the annual showing of the 1969 BofB film, but could take no more when two converted Percival Proctors playing at Stukas, and radio-controlled Stuka models, were shown glide-bombing the Ventnor Chain Home facility with unerring accuracy and to the noise of sirens and without swing-down bomb cradles.
See - http://www.youtube.com/watch?v=RVBO61qg-kc

There were many Germans in the cast, even speaking German to each other, and many obvious efforts had been made to achieve accuracy, going as far as destroying a WWII hangar at Duxford, but I've resigned myself never to seeing a realistic vertical Stuka attack portrayed on film.
Why is that, I wonder?

Tony