Rather than "living" of £200 per week, why dont you make a challenge to see how much you could make of that, or something for example.
Where I live, I could by myself a nice flat for 200k, and get another 2decent 3bed flats easily for under 200k.
Both flats I would then be able to rent out for £900 PCM, so giving provisions for repairs/flats being empty, I could probably garauntee myself an income of £18000PA.
Now the average wage today, is meant to be 20k, or thereabouts I believe, so you would be living of a wage lower than average, but with your £200, and even just a part time job, you could probably afford to take on another property, and pay that off easily to increase your capital.
For instance, with your £200PW atm, what do you want to get out of life?
You could use that to "live" or "travel", and while at home, you could challenge yourself say to follow Donglemouse's footsteps(google) in matched betting perhaps, or do some freelance IT work, depending of what your into.
In essence, imo there is a lot you could do, it all depends on how much you want to live your life/invest in your future.
Best of luck!