Damn…I seem to have just one problem after another. 
This morning Insync kept saying it could not initialise. I tried restarts and reboots and nothing worked. The forum said to delete my Google account, and then reconnect it.
However, now I’m getting thousands of files that were excluded being copied over. (I do a lot of nodejs development, and there’s no point in the ‘node_modules’ directory being copied all the time.)
I can’t be bothered to stop the copying since I’ve got stuff to do…but it would be really, really simpe to store config like that in a plain text file, leave it in the ~/.config directory, and then pick it up again when the account was reconnected.