I would prefer a second hand one, but am happy with new too. Would like to spend up to about £700. Has to be set in white gold, and be quite a big, probably square ish stone. Any good ideas of where to look for one, or any good jewellers you know of that does good second hand jewellery? I'm in Wiltshire, so somewhere fairly close would be good, or somewhere that will send it to me. Tia