Hello, I am Keith, one of the experts on Just Answer, and happy to help you with your question.
I would suggest that you are self employed. You should register with HMRC [the Inland Revenue was merged with HM Customs and Excise some years ago] as self employed. Here is the link:
You should have done this by 5 October, but I don't think you need to worry overmuch on that score. Once registered HMRC will the send you self assessment tax returns annually for completion. For 14/15 you have until 31 October to file on paper using Forms SA100 and SA103S available on line. Otherwise you will have to file on line. On receipt HMRC will tell you how much Income Tax and National Insurance you owe which must be paid by 31 January 2016. If you are an EEA citizen you have a personal allowance of 10.6K to offset your income.
If you are self employed you do not need to quote an employer as you do not have one!
I do hope that I have been able to show you a way forward in this matter.
I also have a regular job in which I am employed by a school. Do I still fill out a return as self-employed?