Need unique wedding rings in the UK fast

My wedding is in exactly a week and my fiancée and I haven't even picked out our rings yet. We've been completely swamped with work and sorting out the venue, so we simply haven't had time to hit the high street shops. We absolutely don't want those standard plain gold bands that everyone else wears. Both of us are hoping to find pieces with a bit of a twist or an unusual design. Can anyone point us towards good places in the UK to spot something a bit different at such short notice?