Thanks, i was unaware of the roundTrip.py script.
 
I did notice that the generated TTFs were different from the original ones.  Just to clarify - when I mentioned that the TTFs were almost identical, I was referring to the the output from the original FontTools and my version.  i guess you could add a flag that applies the optimisations if present, or leaves the bytecode unchanged if missing?
 
Thanks for pointing out the stray "/" change.  I'm not an expert on Git - is there an easy way to revert this one change and apply it in the correct place?  Would I need to use rebase to do this?
 
Similarly for renaming my commit messages to include the prefix - what command would I use to do this?
 
I did find a few fonts that the original FontTools produced errors for.  Is it worth listing those (in a separate post)?
 
Andrew