Can't find a replacement kitchen sink basket plug anywhere! All aspects of plumbing questions and answers, help, tips and information

[Yeobrew]

Our kitchen sink waste basket plug is broken and I can find one that looks the same type anywhere. I've attached pictures of the half sink plug as it's complete and works the same way. This plug twists and drops to make a seal, or pulls up and turns slightly to stay in drain mode. I have spent hours trawling the internet for a replacement but can't find anywhere that sells a model like this that drops down rather than pushes down to make a seal. Any ideas what it's called or where I could get one? Thanks.