Andrew -
Your internet search was correct for American designation of skirt steak. The skirt is really the diaphragm muscle that is located just rearward of the forequarters (brisket) on the underside of the steer. The section from which it is removed is known as the beef plate. The skirt, when trimmed, is usually about 20 inches long and about 3 in. wide. Does that match the cut of beef to which you refer?
"Rearward and higher up" will put you first in the beef loin just forward of the hindquarters. That'll give you top sirloin and bottom sirloin, ball tips, tri-tips and flap meat - another flat muscle from the bottom sirloin.. Move a bit forward and you get your strips and tenderloins. Moving farther back to the hindquarters will give you your inside (top) round. There's also a cut called the "cap" which looks a bit like a skirt steak which is from the round. The "goose skirt" that your butcher referred to is, if I read him correctly, what we call "flank steak".
Hope this helps.
BTW, inside round should do well. Ball tips (bottom sirloin )or top sirloin (a bit pricey) will be more flavorful.
panella