Ady - i was supposed to message about this a couple of days ago but got quite busy.
I'm not sure if this will help in any way when it comes to your models etc, but i just saw in the shops here in Australia a new set of fortnightly (i think) Star Wars magazines called 'The Official Sharships and Vehicles collection'. With each magazine you get a different 'ready made' miniture model with it that i supposed could be used when refilming some of your scenes.
Looks like you've got it in the UK as well - http://starwarsvehicles.deagostini.co.uk/
Cheers
Ben