Hello,
There are two main master's programmes I can recommend in the UK, King's' and UCL's, both based in London.
I went to UCL so I am biased. King's has a longer tradition of "humanities computing" as a discipline, though.
In my experience you will need at the very least £1000 a month to survive in London. Cost of accommodation in student residences is charged per week. Prices here:
http://www.ucl.ac.uk/prospective-students/accommodation/residences/feesUnless you have a EU passport, I cannot emphasise enough how important it is you check the student visa requirements.