Unicorn Accountants London. Affordable accountant & payroll services in London for small to medium-sized businesses. Xero Accountants & Bookkeepers in London Accounting services in London provide an option for any small to medium sized business, our team provide cost-effective services which are affordable for a range of different company sizes and across a variety of sectors. Our accountancy services can be utilised by any company with a requirement for an honest and reliable accountant in London and surrounds.