Self-employed registration/tax (UK)

Apologies if this is something that has been covered elsewhere, my searching through the sub didn't bring it up.

I have been accepted to, and am starting to do tasks for a handful of online survey/user testing sites, looking to earn maybe £200ish a month from them.

I have also been accepted to work for Lionbridge and am waiting for the email to take the Maps test (any tips happily recieved!). I know that I have to register as self employed and pay tax on what I earn from Lionbridge, but my question is do I have to do the same for the survey sites? I am in the UK.

TIA!