3- How much would cost a month of living in London? Any other place you'd recommend?
London is very expensive compared to everywhere else. Wages are generally higher there but you will still end up with less disposable income. Would imagine you'd struggle on anything less than 25k a year, would depend on your lifestyle I guess.
I have just finished living in Bristol for four years while I was doing my degree, it's a good city with lots going on and cost of living isn't too bad. Good nightlife too.
Have now moved back up North to home and am going to move to Leeds. People tend to be a lot friendlier up North and the cities are always good nights out, cost of living will be cheaper compared to London as well. Manchester is also a good place to be with lots going on, as is Liverpool which is much better than it is stereotyped to be.
I am probably slightly biased but not a big fan of London, I have a lot of friends that have moved there after Uni that I've visited several times and would only move there if i had an amazing job offer etc. Apart from that its just so overcrowded, especially with transport and people seem to be generally unsociable.
And yeah, as keoghh said, weather is going to suck compared to Spain, lol.