Hoover HNL6166 is burning clothes!?

The machine is just over two years old and has been working okay up to this point. About two weeks ago after doing a wash the door was opened to discover a horrible burning smell and some damage (burn marks) to certain clothes items. The rubber seal to the door was obviously rubbing somehow as bits of this grey rubber were all over the clothes and drum. So I did some online research and found the correct door seal, and bought it for about £15. I managed to fit it with some difficulty and tried the machine on a cycle (empty). I had also cleaned out the filter and gave the motor brushes a spring clean too. The machine worked okay empty, so I tried a half load, again fine. I left my wife to carry on with normal washing (full loads) but she has just told me that the same thing has happened. I feel sure that somehow the drum is vibrating against the door seal and causing a friction burn, but am stuck as how to rectify this fault. Any ideas?