If my employment income is calculated for the tax year 17/18 and my trading profits are from Jan17 to Dec17, in order to calculate my income tax liability – do I need to apportion my trading profits for the 9 months (April 17 to Dec17)?
Your question clearly indicates that you have not studied the OT notes or watched the lectures on chapter 6 that deal with the bases of assessment for the unincorporated trader – you must study the OT notes and where available watch the lectures. Re your question above – if you study the notes then the first page of chapter 6 will show you that you do NOT apportion those profits.