Thanks your your post G-I-B and CAVORTINGCHEETAH what is was i trying to suggest about the A321 and the B757 but you have put it across in a better way it seems that Andy S missed my point, so give or take the A321 and the B757 are the same size but produce greatly different vortex tendencys.
Lets hope the A380 is not as bad as we all think as new technology should help reduce these nasty little blighters !!