The marks on your porcelain tea set are those of James Herbert Cope, producing at the Wellington Works, Longton, UK, 1887-1946.
See the following image of a slightly smaller and later set than yours by the same maker.
It shows an Art Deco - late 1920s- 1930s- set with the same marks as yours that sold at auction for $40.05. I saw another that sold for about $24. Then I saw where a cup, saucer and tea plate sold for $8.44. All these are auction sold prices.
Taking into consideration that your set is slightly older and larger, we can assume the estimated auction value of your set would be about $60-70.
Furthermore, the estimated retail value would be $130-160.
As for where to sell.....If you want to sell quickly at wholesale prices, try one of these sites.
I do not know where you live so I will make suggestions for three countries.
Online auctions like eBay generally bring wholesale selling prices.
If you would like to sell close to estimated retail, some ideas are:
The internet has your largest audience of buyers. Place small ads on these sites or set up your own small store on these sites.
Etsy.com - small fees - 20 cents to list plus 3.5% final price.
Amazon Marketplace: http://services.amazon.com/content/sell-on-amazon.htm/ref=footer_soa?ld=AZFSSOA
Your nearest Craigslist.com
These sites are excellent and more upscale but fees are higher. I only recommend them if you have several items to sell.
In general, a private seller to a dealer or at auction can expect 30-60% of estimated retail value.
You can set the retail price at what you see others are selling for in retail shops online or in the retail shops around you.
I hope I have helped you.
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