Default [Q] Downgrade to earlier KitKat version

Good Evening Chaps!

I have a little query with regard to whether it is possible to downgrade to an earlier version of KitKat.

Now its not going from 4.4.2 back to 4.4.1 simply going from 1 build of 4.4.2 to an earlier branded version.

The reason why is that I have to send my phone for repair and they advised that it would need to be back on the branded ROM.

The download seems to take forever (I'm on a 512k connection), now I don't want to download both of the roms @ 2.5GB as I would be here for days hence the reason for asking if it was possible?