how to fit an electrolux door seal?

Hi, My daughters Electrolux Ew 1000I washing machine door seal has come off at the drum. Ive managed to put it back on with great difficulty but wonder whether there should be a retaining band holding it to the outer drum. Its impossible to see or feel anything and nothing has dropped down underneath.
I have left it not leaking but am unsure about it.
If it did need a retainer, or the old one is still on how would i get to it please.
Thanks.
Dave.