Interesting postcard. Printed in Germany, published in London. It’s pre-WWI. Addressed to a party in Gate City from “Guess Who” in Kingsport, but never mailed.
The “London E.C.” stands for London’s East Central Postal District.
B & D, Pictorial Post Card Pioneers, (Blum & Degan) operated in London from 1885 to 1908, when they went bankrupt.