Thank you prompt reply.
In the absence of good accounting records maintained to enter all jobs whether paid cash or otherwise, here is a practical suggestion.
Prepare a schedule and list all the cash jobs with the amounts received from your written (rough) notes.
If you have spent any money on those jobs, make a listing of expenditure with dates if possible. You may be able to extract information from bank statements/credit card statement etc if you used either of those as a method of payment. Have a best estimate if actuals are unknown but you should be able to support the expenses if asked by HMRC . If you are not able to do that, then don't put expenses as they may be disallowed.
Now you have got your statement of income and expenses.. use this figure to complete your supplementary pages covering self employment. I presume your income was below £79,000.
Enter turnover in box 9 - Your turnover. If your annual turnovee is below £79,000 you may put your total expenses in box 20 - Total allowable expenses rather than filling in the whole section.
I hope this is helpful and answers your question.
If you have any other questions, please ask me before you rate my service – I’ll be happy to respond.