As a fellow British small business owner I assume you're familiar with the UK's self-assessment scheme as well? I've always found it to be very quick and painless, and unlike the US system there's no need to get an accountant or even any specialised software involved.
I was really surprised how easy it was, it takes maybe 10 mins if you have the information and logins to hand.
Honestly I can't think of many ways to improve the UK's online accounting process from either an employer or employee's standpoint because I already spend less than a day total per year on it.
