interesting way round you want to do that, usually the film would be made first and a trailer produced from that. Can I ask why you want to make a trailer for the script?

People often have it out for VFX but most of it is totally invisible, often fixing mistakes like hiding crew reflections/rig cleanup etc or taking out signs or adverts that appear in the background. VFX has become such an essential part of the creation process that every single film and tv show made now has some shots that utilise digital cleanup or full CGI sequences.

If you haven't seen it yet, I suggest watching Rocket Film School's video on CG
https://www.youtube.com/watch?v=bL6hp8BKB24
It's a great example of why people seem to hate on our craft and why it is so essential to the film and tv pipeline now

Being from the UK (and working in VFX there) I am super happy that it is now being used so frequently for film shoots. It means in turn that the post production side also grows and means more work for all of the talented artists and creators we have.

Also gives me a great deal of pride knowing all these great films were shot here - especially Star Wars. I am a massive SW fan.

What about UK laws?
They seem much more confusing, I'd be greatful if someone could clear them up for me