The mark is that of Gustave DeMartial & Cie dating 1883-1893.
The estimated retail value of each cup/saucer set is 25-30 GBP.
As for where to sell.....If you want to sell quickly at wholesale prices (30-50% of retail) try one of these sites.
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 fees-20 cents 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.
Packing porcelain from Haviland International:
1. Start with a layer of packing material such as bubble wrap, packing pellets or poly foam at the bottom of a sturdy box. For shipping some items it may be better to use more than one interior carton if more than one item is being shipped.
2. Heavy items, such as pottery, platters, tureens or vases must be wrapped in large bubble wrap (two layers is even better) and placed in smaller separate boxes before adding them to the larger outer shipping carton. This is known as DOUBLE BOXING, a box inside a box.
3. Begin packing the box with the heaviest items, then proceed with the lighter items as you fill the box.
4. Wrap plates, bowls and serving pieces separately in bubble wrap. Heavier pieces and delicate items need to be wrapped in large bubble wrap. To ensure that the wrapping stays in place, secure it with a small strip of tape or, better yet, rubber bands. Rubber bands are easier to remove, as they do not require a knife or razor blade, and will stretch and shrink as the ambient temperature changes.
5. Fill any empty space with styrofoam peanuts (or crumpled newspaper, or ...) to prevent contents from shifting and to keep the box firm.
6. Add a final layer of packing material to the top of the box before you seal it to prevent the contents from shifting and to keep the box firm.
7. Label the outer shipping carton with FRAGILE labels.
8. If you are willing to drop the box to the floor from a standing position after you have packed it then you have probably packed it correctly.
Following these instructions carefully will prevent problems for both buyers and sellers.
Depending on the value or importance of the pieces being shipped, you may wish to consider using plastic boxes (Tupperware, etc.) as your interior containers after bubble wrapping each piece individually. These are much less likely to be crushed if the parcel receives rough handling in shipment.
It is recommended to use Priority Mail insured or UPS for your shipments*. Parcel Post may take up to three weeks to reach the destination and the parcels are handled more frequently.
* It is not recommended to use FedEx to ship porcelain and glass. The fine print on their website states that their limit of liability for these commodities is $100, regardless of how much insurance is purchased at the time of shipment.
UPS shipping guidelines for porcelain and glass require that each piece be surrounded on all sides with two inches of packing material. This may seem excessive, but you will realize that this is only to try to guarantee safe arrival, especially when you open an improperly packed parcel that contains broken pieces.
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.
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