www.folksy.com is a brilliant place to sell your work as a designer / maker based in Britain. It's a 100% British, 100% handmade market place. No vintage, no re-sellers allowed. You can sell craft supplies too!
I'm slightly biased as I have worked for this fantastic team in the past, however in a way that has given me the insider knowledge that Folksy is a handmade marketplace that genuinely want to help British craftsmen thrive! No business men in suits, they're a small team of people passionate about craft and making.
Read more here on the Folksy Blog - The British Alternative to Etsy