Cool, glad I was on the right track. I didn’t try Remove Local Content however it did download the new version into a separate folder in my Marketplace Vault Cache so shouldn’t have got any of the old stuff at that stage.
However I do have to import into a separate project and Migrate into my main project since I have a different folder structure in my main project. I checked out all files under Chameleon/ in source control (Perforce) then used Migrate to overwrite them. Possible there’s something hanging around from the older version but I would have thought all the references would have been updated as well?
Might be some sort of struct weirdness, as they are pretty flaky at times… All is working fine for me now after replacing the missing default T_White in both the structs.