I own a towbar fitting company, keeping the caravanners on the road, sorry!
Yeah, it's illegal, should fail an MOT (If the tester happens to know a CTR shouldn't have a towbar.), will invalidate suspension/chassis warrenty etc, etc.
But, for example
http://www.witter-towbars.co.uk/FittingInstructions/HN51.pdf. Witter are the biggest UK manufacturer of towbars, and nowhere on the fitting instructions does it say excluding Type R, in fact no towbar manufacturers instructions say excluding Type R.
So any uneducated towbar fitting company, even Honda dealer, wouldn't realise that they shouldn't be fitting a towbar to it. I've been asked to quote a few times for them, if I didn't own a CTR I'd have looked in the catalogue, quoted a price, and got the lads to fit it being none the wiser that it shouldn't be done.
It's a bit worrying really, but the CTR is one of the few exceptions where just one model range cannot have a towbar fitted. The Seat Cupra range is the same, but only certain models, then it really gets confusing!
My god I'm sad!