Much like Goldilock's porridge...this D shape toilet seat is just right...

At a length of 449mm it is right in the middle of its sister Short D (424mm) and Long D (467mm) seats from Euroshowers.

Sometimes being the middle child is a good thing.

https://www.replacementtoiletseats.co.uk/ourshop/prod_5902839-Euroshowers-Middle-D-Style-toilet-seat-in-Duroplast-White.html