We used C4 Print for our Kate4Gilmore campaign. They did both our Corflute Signs, and work with us to design and make stickers that we could put on cars (we ended up with 100 cars with stickers. )
They were fantastic to work with, and the stickers and product they produced were exactly what we needed. Their costs are also very sharp. I would definitely use them again.
heres an example of one of our stickered cars!