Wow, this might be a late response to your question but I too have dreamt of doing a Dieppe Churchill. I've done a lot of reserch on the matter and have come up with two possible source for decals:
Cromwell Models has old Dieppe decal sets for these churchills tanks but I have no idea if they're still around:
http://www.xs4all.nl/~cromwell/35Church.htmlSecondly, before AFC CLub announced their release of the new Churchill Mk III model I had purchase a few Tamiya Churchill Mk VII tanks with the IMA Mk I and Mk III conversion sets. Given the poor instruction sheets I opted to wait until I had more patience to stumble through the conversion blindly...
In the mean time The Through the Lens book described above is probably the best source for photos. Also Armour Acorn has alot more of the markings:
http://www.armouredacorn.com/cvm.htmlI've opted to use UltraCast decals sets as they have decal sets specific to each Canadian armour regiment including the Calgary Regiment that landed at Dieppe. The UltraCast decals sets are labeled Italy 1943-1945 but they are the same unit markings. I also picked up a couple sets of generic Commonwealth Tactical signs & Numbers in white and blue for the rest and the names to complete the model. Check out UltraCast and hopefully they can help you out:
http://www.ultracast.ca/armor.htmAlso, I don't consider myself a bolt counter but the Churchills that landed at Dieppe had the early style plate tracks and to my knowledge the only company that makes the Early style tracks is IMA (International Model Asia) I stumbled upon a set on Ebay and I know they're listed on the Mission Models website as a supplier. I have heard some disappointing news that they are hard to come by, so it might be worth trying to order them driectly from IMA.
Hope the build goes well, I'll try and follow your build if you continue with this thread. Cheers!!