Is income tax payable on winnings/awards from online quizzes, surveys, etc?

Hi, I am a UK-based employee whose income tax is paid entirely through the PAYE system. I currently have no other sources of taxable income and have never had to register or submit a Self Assessment return to date. I have recently started investing, but all of my investments are contained within a stocks and shares ISA so there should be no UK tax liability in respect of dividends received or capital gains. I am looking to supplement my main job income in the form of online quizzes that offer cash prizes, completing surveys, offers and similar activities on platforms like Swagbucks, but the tax implications on such activities are somewhat ambiguous to me. I know there exist trade allowances for most side hustles, but most of those relate to the buying and selling of goods, or providing a professional service such as freelancing, neither of which apply in this situation. Would I be entitled to any such allowances or reliefs if I’m making, say, £50 a month from using these apps? Would I be required to register for and submit a Self Assessment? This would be nothing more than a casual hobby if that makes any difference. Many thanks. - Dan

Hi,
Prize money, goods and any incidental expenses awarded on entering competitions, quizzes, surveys etc.  would not be considered as taxable income.  
Thank you.