Estd. 1774 Cauldon China england help

I found these plates today at a thrift store and was wondering if any knows anything about them I cannot find much but they all have that same exact writing on the back. I found each on ebay for but they don't say "est 1774" and I'm not sure if that matters I did put them up to light and can see the shadow of my hand through the plate if that helps any thanks in advance.

 

This has a bit about the 1774 mark: http://www.thepotteries.org/allpotters/261.htm

 

They're post war - 1950s ish.