I ended up sending out lots of emails and these guys were the only ones that had the templates for the GC at the time:
Ended up getting an upgrade to the top ones as their template was wrong (BMW had sent them the wrong mats i guess, from which they made the template) so had to send them a template of mine. Worked out a quarter of the price of the BMW ones (which weren't in stock anyway) and quality was only a shade under (once I got upgraded to top ones). Good enough that I end up using them quite often (just rotate with originals, giving them plenty of time to dry after a shampoo, ivory picks up a lot of dirt as you may expect).
I would assume BMW have the GC mats in stock by now, and I'd also imagine a few other suppliers have templates aswell.