To live comfortably and excluding tuition (as you've mentioned that above) and taking an average price of £110 per month rent (i.e. you share a £220 per month flat with someone else who pays the other half) I would say that you would need about £300 per month.
I've seen people live on much less than that and much more than that so it is very rough estimate and assumes you eat a lot of takeaways instead of cooking.
Hope that helps
And Allah Knows Best