Your jewelry looks really nice. Your prices seem to be a bit low.
IMO, you should not yet have opened a store.
You don't have enough inventory and are paying for a store, your listings and FVF fees on eBay and PayPal.
You will be losing money.
You should start with regular BIN's or Auctions. I am not sure if the UK offers the 50 free listing per month but I am sure they have monthly promotions otherwise which you are also not going to be able to use as a store.