Permitted work

I only do one hour a week mowing a friend's lawn, and he pays me £12. The DWP usually send me each year a PW8 form. I've just received a B1603/21 form, it's got 12 pages, it seems it reads like if someone as a proper self employed business. I'm confused what to do. Should I go to my local DWP office or fill out the form as best as possible?

Thanks I was going to write on the front of the form that I still do 1 hr per week and get £12 gain, and send my last two months bank statements that they usually want when they send me the PW8 form.

I went to my local job centre, the DWP officer I saw said they don't deal with ESA any longer only UC. Anyway he filled out the B1603/21 form for me, most of the answers where no and N/A. He said the form is an old one, and doesn't fit to modern benefits. He said that I may get a call from the DWP for more info. He put my form in the internal post.