Vinted, eBay, Etsy and Depop all have to tell HMRC about your sales once you pass a certain point — but that's a completely different thing from actually owing tax. Two minutes below and you'll know exactly where you stand.
If it's useful, feel free to share it with anyone else who's asked the same question in the comments. And if you want to see the fuller version — tracking this as you sell, not just a one-off check — there's more at ovrilo.co.uk.