Selling on eBay and vinted

Hi. I am an occasional seller on Ebay and vinted, just outgrown clothes and shoes or toys the kids don't use anymore. I'm not a reseller. I do probably sell more than the 30 items a year though but I do have four kids so there's always been a lot of outgrown stuff. I am already registered for self assessment as I have an etsy shop and I fill out my tax return each year online. My profit is always below the threshold so I have never had to pay any tax so far. Should I be including the little bits I sell online? Each item is normally only a few pounds, I don't buy to sell, just trying to recoup the costs of having a large family. Thanks in advance.

Hi,
You can check below if you need to tell us about additional income:
Check if you need to tell HMRC about additional income 
Thank you.