It's not in Canada either... still haven't figured out why that is. Think it may just be the nature of what gets towed in the UK vs. NA and the general knowledge levels as well. Basically Mazda NA doesn't want to deal with a whole bunch of idiots who have killed their engines/transmissions trying to tow their 5000 lbs boats!
Anyway... you had to drill holes to install your hitch?? Why didn't you just buy the U-haul, Hidden Hitch, Curt or Draw Tite hitches made specifically for the 5? They all just bolt onto/into existing holes, very quick and easy to install. This is a great site to find hitches, ball mounts etc... based on your vehicle - http://www.etrailer.com
I bought the hitch on etrailer indeed. Believe I needed to drill, but don't remember for sure. Might have been on our Subaru...