For John Chapman:-
The food mill is NOT a sieve so won't necessarily remove seeds. It's for pureeing food. If you want to remove seeds you need a sieve.
"There was too large a gap between the rotating part and the sides and sieve. Little went through it." As regards this comment, you probably put the plates in upside down. They should be domed up when in use not down. They will then make contact with the back edge of the blade. The front of the blade is raised above the plates in order to gather the food to be pureed and direct it back to where its back edge is in contact with the plates and can scrape it onto the plates.
I hope this makes sense to you