Have same problem. Had a man in but only lies.
Trust me, it's not the bearings and it's not the pump. He took off the pump after saying that was the problem. At my request he restarting with pump removed noise still the same.
Bearings make a fairly continuous grinding noise, but I think my problem is a key somehow under the drum that catches occasionally and then makes a horrendous clattering. Don't be misled, especially by foreign repair men who are just guessing and revert to very poor English when questioned.
Clive, October 2011