This is so rough it's mostly just notes for a strip. But, hey. (Here's the Catherine Tate Bing-Bing reference if you haven't seen it. Or here.)
I just got the Association of Illustrators mailout with a reminder about the Business Start-Up Master Classes for Illustrators in London. No idea if they have any spaces left, but I did most of the classes and they were really helpful and good value for money: subjects such as portfolios and agents; how to make money; tax and book keeping demystified, and a some others. They're good hard-core info if you're trying to make a living at this. Details here.