"I provide my services under contracts..." - do I tick this box?

I am completing my Self Assessment tax return and trying to figure out whether to tick the "I provide my services under contracts for professional or other services and these contracts span my accounting date" box. I am on the cash basis and have a relatively small turnover of around £15,000 per annum. I am a Private Tutor and sometimes parents will pay me for a few lessons in advance. A couple of times, one or two lessons paid in advance have fallen in the following tax year. Do I need to tick the box?

Hi TaxQueries278,

If you're carrying on a trade, profession or vocation and have received income from contracts for professional or other services, then you will need to change the way in which you calculate turnover in your accounts. This is because there has been a change in the accounting guidance on service contracts for accounting periods ending on or after 22 June 2005. 

Thank you.