Graham, I have a tee shirt that says that which a friend gave me about 6 years ago which I currently am wearing. There is not a 'R' or 'TM' just a grey tee and forrest green letters. Don't know if that helps or not but but they have been around. Because the US is so 'legal oriented' a TM/R search should pull up something if there is.

Keep us informed, mine is starting to show the age and I had been thinking of doing one up myself to replace this one.

RLJ-