Update for those still with the will to live - put it in the diswasher
and then wrapped elastic bands round lid and body and got the lid off.

The washer/seal in this one is wider and without a tab - see pic - and
so jams the top. I'll email the store in Florida and test their
customer service€¦

http://www.flickr.com/photos/49435266@N05/8562056469

E.