You can find your turnover in Box 9 on page 1 of the sa103s section of your tax return, and it’s on the same place on every tax return.
124 City Road
London
EC1V 2NX
Penstranze Business Centre
Truro
Cornwall
TR4 8PN
Monday to Friday 9am-5pm
Registered in England & Wales | Company Number 11373381 | ICO Registration Number A8255161 | HMRC AMLS XRML00000190406