Ahh - I forgot that the v1 template change had been done manually, and I removed it.
I also figured out why it wasn't working for me - it doesn't seem to obey the permissions of a user's additonal groups - only the primary group. Is this intended behavior? Or perhaps due to "Allow Users to have Member Groups" to 'No' in my primary usergroup?
Do you have a query to enable PM Search for all usergroups?