Not sure whether you're talking about emerald or tourmalines. I presume it is the Gems of Distinction range and if it a tourmaline necklace we're talking about I would go back to Gems boutique web-site as a 250ct multi colour tourmaline necklace can be bought on line for £157 and possibly cheaper than your auction price (it happens sometimes which is why I always check) If it's the sapphire ruby emerald necklace you're alright.
I have't bought the necklaces as I wouldn't really have the occasion to wear them but I have bought many of the bracelets including the multi-strands in emerald, ruby, sapphire and the tourmalines. Personally I think they're great and they always receive positive comments as they really are lovely and the colours and matching are pretty spot on - BUT if you're unsure you might want to have a ferret around a certain on-line auction site where these multi strand necklaces can be picked up even cheaper (I know as a friend of mine picked up a 300 ct ruby, sapphire, emerald necklace very similar and great quality for about £100).
Hope that is of some help
