Well it's about time...

https://www.replacementtoiletseats.co.uk/ourshop/prod_7710398-RTS-Opal-WELL-Small-Oval-Slow-Close-Quick-Release-Toilet-Seat-350mm-width-88216.html

The RTS Opal Well 350 oval is back in stock.  One of our most popular top fix slow closing seat with quick release hinges.