Here's how to avoid wasting your money on a fake Sweetie Bracelet without having to take delivery to find out it's a dud.
Ask the seller to tell you whether or not one of the small links/beads is hallmarked as 925 with a full set of British hallmarks. The fake sweetie bracelets are never hallmarked in this way. The hallmark usually appears on one of the small links on either side of the main washer with the 'Links of London' stamped on it, usually 1-5 beads along.
Ask the seller to let you know and to publish your question on the auction page. If they will not do this then they are admitting that their item is not the genuine item.
By the way, 99% of the Sweetie bracelets on Ebay are fake. None of them are worth even a tenner.