The constant stream of changes to tax legislation means not only are the returns becoming more complex, but taxpayers also risk incurring penalities through failing to complete their returns on time or correctly.

The aim here is to save you a lot of time, worry and money by handling your self assessment for you.  The standard service normally includes all the necessary computations, completion of your return and general advice on how you can minimise your tax liability.  

For the self-employed, tax rules are quite different from those of an employee; instead of tax (and national insurance) being deducted from your earnings at source, you'll receive a bill at some time in the future.  It's therefore sensible to budget accordingly for this financial commitment.