I am touring in the middle of the year also. I lived in the UK in 2008 for 18 months, this time my BF and I are just going for a 6 week holiday.
When it comes to where to live I suggest waiting till you get over there to decide. Book say 2-4 weeks in a backpackers and then get out meet people and go out in different areas.
It depends on how much you are willing to spend on rent also. 2.5 years ago a room in a share house vaired from 80 pounds to share a bedroom with another female (2 single beds) this excludes throwing in for bills.
If you want your own room it started from about 150 pounds up to about 300 pounds a week.
It alll comes down to the location, whats included, the state of the property eg: newer / older, how many other people live in the house all that sort of stuff.
Here is what my low down is on a few suburbs, I was 23-24 when I lived over there
Hammersmith, Shepherds Bush, earls court= Heaps of auzzies, close to the city, 5-10 min bus ride to Kensington. auzzie pubs (cheap meals cheap drinks) easy to find share accom. Bit older and dirtier the Hammersmith council did not remove the garbage enough, Also other than a lot of Auzzies there is a lot of Indians and people from other middle eastern countries, I lived in Shepherds Bush for over a year, suited me as I paid 160 pounds for my room.
Fullham- Great place to live if you can afford it. Felt a little safer here, clean streets still a big Auzzie comunity, pubs and bars a little more up market. Around 200+ pounds for a room
SoHo, Kensington, Knightsbridge- Expensive but in the hub, expensive everything not as many Auzzies but really nice its like the Double Bay (Sydney) of London. Its upwards of 250 300 pounds here for a room!
Up North on the Tube around Camden is nice too…
Look on Gumtree website for share accom in London.
My tips share with a good girl guy ratio, dont live with more than 5 others less the better and dont budget more than 1/3 of what you will earn to pay rent cause it is so so expensive to live in London! Also stay inside zones one and two on the London tube map as its closer to the city and cheaper for a weekly ticket.
Hope some of this helps