After remoting into another company's site (using Open VPN) and connecting to a machine their end to access their Accounts databases, I realised my printers hadn't been carried over by Terminal Services.
First guess was a GPO was stopping the printers redirecting - which turned out to be correct. Disabled the GPO, still didn't work.
Checked Event Viewer on the remote machine and there were errors stating that it could not find drivers for the relevant printers.
The driver install files that I would use to install the machine locally normally don't contain any .inf files meaning I can't just add a fake printer and point it to the drivers just once to get it installed...