The mark is a 19thC for Francis Garner of Verbilki (near Moscow), Russia,
Francis Y. Gardner, an Englishman, established a private porcelain manufactory in Russia. His wares were among the most popular of the 19thC.
Your cup and saucer have an estimated retail value of 110-140 GBP in an upscale venue.
Online auctions like eBay generally bring wholesale selling prices (30%-50% of retail). Sales in the eBay "Buy It Now" format are closer to retail.
If you would like to sell close to estimated retail, some ideas are:
The internet has the largest audience of buyers. Place small ads on these sites or set up your own small store on these sites.
Be sure to specify a local pick up only for large items. That way the buyer would be responsible for obtaining his own insurance and transport.
These sites carry antique as well as vintage items.
Accept PayPal only.
Etsy.com - small fee to list plus 3.5% final price.
These sites are excellent and more upscale but fees are higher. I only recommend them if you have several items to sell.
Or your nearest CraigsList.com, nextdoor.com, Facebook.com, or Facebook Marketplace where you can list items for free. Accept cash only.
Ultimately, to obtain these retail values we assume the piece or set is in good condition and that the final value depends on sale geographic location.
In general, a private seller to a dealer, via consignment or at auction can expect 30-50% of estimated retail value.
Insurance replacement values are usually about 20%-50% more than retail values.
I hope I have helped you.
If I can help you with further questions about this answer, please let me know before you rate me.
I endeavor to give realistic, honest answers in a timely manner.
Please do not rate the appraisers for any issues you might have with the site, appraisers are not employees of the site, we come to the site to answer questions the customers have.
Please let me know if you have difficulty with the site's rating system.
To complete this transaction, please click the five stars at the top right of your screen and hit the submit button. Or if you see "review expert" or "rate expert", you can click on that.
If you are using a mobile phone: scroll to the top of the page then click on Finish Rating, then click on the stars! This allows me to be credited by JA for my Knowledge, Time and Effort.
Rating me does not cost you anything extra.
Bonuses are not required but are always appreciated.
If you would like to use me on any future questions, requesting me expires in a short time. If you type "FOR DORIS" as the first TWO WORDS of the question, I should be able to help you.
You can also add me as a 'FAVORITE' to your personal expert.