"Wilmslow" is the name of a pattern of china dinnerware made by the firm AG Richardson under the name Crown Ducal.
The Stoke-on-Trent, Staffordshire, England pottery of AG Richardson operated from 1915 until 1974; first at the Gordon Pottery, Tunstall (1915-1942), then at the Britannia Pottery, Cobridge (1933-1974). They are mostly noted for designs by Charlotte Rhead who from about 1935-1945 designed many products made using the tube-lining technique. They are also noted for chintz style patterns.
But this doesn't include the Wilmslow range which is a straightforward floral design; I don't know when it was produced but my guess is around 1955-1960. AG Richardson was owned by Joseph Harrison who lived at Congleton and may have picked the name "Wilmslow" simply because he lived not too far away. Crown Ducal Wilmslow isn't a particularly valuable china pattern so you can buy pieces at quite reasonable prices. If you have any further information on Crown Ducal Wilmslow then please email me. (But please don't ask me any questions because everything I know is already on this page!)
If you're interested in buying Crown Ducal Wilmslow china, or any other Crown Ducal china, there's usually some available on eBay, from where you should also be able to divine the current value of almost any piece. In fact I've noticed the amount for sale has increased substantially since I first included this article (which now gets lots of hits) e.g. there are 5 items on today whereas it used to be one item every few weeks. The minimum asking prices seem to be creeping up - on the other hand there aren't many takers.