Paul McCann wrote: (nice start to the week: replying to myself...)
I think that TM_GIT should be set to the *directory* in which git lives. So chop off the final "/git" and you should be ready to roll.
Sorry: please ignore the above paragraph. It should be set as described in the initial post. I should read the README before making stuff up.
Alternatively: I've got a symlink at /usr/local/bin/git which points to the same location as your git. This also works fine (without any need for TM_GIT to be specified).
Cheers, Paul