Shooting a film

thanks for the link, i'll check it out in more detail when i get a chance, I hadn't looked into the stepping problem, but i'll get it sorted for the final thing

the main problem is the rolling shutter, but the only way round that is another camera or expensive software that i don't have

Rolling shutter is fairly easy to solve too, you just need to offset the camera's sensor readout in post, as the read out is very fast (but not universal so as to avoid rolling shutter) and the finest resolution you can employ in post is 1/25 (or 1/29.97 or 1/24) you need to do a bit of clever maths combined with some pixel interpolation.

I worked it out for After Effects but the same technique would work just as well in any NLE or compositor that have some form of pixel interpolation (Timewarp, twixtor etc).