Frame Cutting a Photron Fastcam TIFF Sequence from 50FPS to 25FPS

Hi all

I've just sat down to offline an ad only to find that all of the footage from the slo-mo stunt day was shot on the Photron BC2, including the footage that is supposed to be 25FPS. The Fastcam only goes as slow as 50FPS.

Does anyone know of a fast way to frame cut the sequences, maybe in finder with automator? Basically I can't make movies to work with in FCP as the online house needs EDLs that refer to the TIFFs and since 1 shot alone has over 7000 frames it's just not possible to do it manually.

Any help is gratefully received.