If you want to be qualified to carry out statutory audits for limited companies, you'll need to become a qualified accountant. See here for details:
http://www.learndirect-advice.co.uk/helpwithyo urcareer/jobprofiles/profiles/profile187/
However, for the type of role you describe, it might be sufficient to qualify as an accounting technician. See here:
http://www.learndirect-advice.co.uk/helpwithyo urcareer/jobprofiles/profiles/profile128/
An alternative route would be to forget about anything which uses the terms 'accountant' or 'accounting' and study to become a Certified Bookkeeper:
http://www.book-keepers.org/
However, with the exception of statutory audits, you don't actually need any formal qualifications. I've kept the books (and sorted out VAT, PAYE, etc) for several businesses without holding any relevant qualifications (except a degree in Mathematics).
Chris