Having spent years renting, I honestly think that a flatshare in London is the best way to go. If you are on your own you may only be able to afford a very small place, and will be having to pay all the bills on your own. Sharing is a good way to reduce your costs, you could potentially live somewhere really very nice, and if you are new to a country it is a good way to meet people and make friends. And if you don't like it, you can always move out!
Vicky