The most boring talk I attended at Loncon3 was the one about Tax for Writers. It was also the most useful. HMRC were there to encourage writers to claim as much tax back as they could when filling in tax returns. The presenter (and okay, he wasn’t boring, he did a very good job) was at pains to point out this wouldn’t turn us into Starbucks or Amazon, it was simply the way the system works.
The best place to go to for help is here: http://www.hmrc.gov.uk/startingup/help-support.htm. I’ve been filling in tax returns for my writing for years now, but I still found some useful stuff there. I’d recommend any UK writer to take a look.
All the above is a huge misdirection, of course. Our overly complicated tax system is just a way to keep an excess of accountants in work, and to allow the rich and powerful to shirk their social responsibilities. If we were to simplify the tax system, a lot of very clever people would be freed to find useful employment, working for the betterment of humankind rather than simply to enrich themselves and their masters.
If you can figure out how to bring a simplified tax system about, I really hope you will do so. If not, you might as well try and get some money back out of the existing one.