So I'm also in the UK, and also aiming for a generally approximate figure of £0.25M as "covers expenses". In my case, I haven't factored in food and other recurring irregular costs, that's just for the relatively fixed expenses.
Your figures seem about right, especially since I currently have two houses to cover bills for. Just don't feel that you have to post every day; I had a monthly blog for a while, and even that started feeling too much like (more) work after a while ;)