Yep spot on, the rings should all rotate freely in their channels
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I would always replace them. You will be amazed how flexible and springy a brand new set is compared to a 10 year old, brittle, crumbly set.
Glad you found a new cover! £110 is a tad rich though. I got one off ebay for £40 and threw it in the dishwasher, came up like new
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