I seem to remember that Max Boyce recorded songs in the 70s that included something about a rugby tour ... might check out his recordings for something bawdy ... of course the Welsh play pretty good rugby (well, they used to when Boyce was in his heyday) ... although I might point you in the direction of the Canadian service song "THE NORTH ATLANTIC SQUADRON" (it's on the database) which I recall being sung with some gusto by Canadian military ruggers in Germany at the Munich Sevens Tourney (and also at Lahr in a earlier event best kept classified).