Corporate sponsorship is all well and good, and certainly merits discussion. I almost regret referring to it though because I want to make sure my main point doesn't get lost here: that on the cottage-industry level, the self-assessment income tax form can actually be unexpectedly useful.

I have to fill one out once a year anyway because of earnings for freelance writing and (music) journalism. But I play gigs as a musician. I also put on gigs for myself and others. So I gave myself a company name and description that covered all these interests. Any losses in one activity are expenses absorbed by the tax I pay on profits from a different one. I would recommend any other 'multi-taskers' do the same.

Maybe if you just put on gigs as a 'serious hobby' one evening a month alongside your PAYE day job you might not think it worth the hassle of getting on the self-assessment form treadmill – but if you were serious enough to be planning on doing so for longer than a year I'd still recommend it.