Thanks for that Rob,
Now that I’ve read your reply (by the way, what are you doing answering on a Saturday?!) I’ve realised my issue isn’t Team Drive/Template gallery, but the Autocrat mail merge Add-on doesn’t play nice with Team Drive (see your bit about some ‘Add-ons’ not working within the Team Drive environment). LOL!
Have a great week – great to see you yesterday at the SEO meeting!