Here's mine
https://www.cousinsuk.com/product/si...ubmariner-more but I see they have a better version now which I suspect is more supple:
https://www.cousinsuk.com/product/si...ex-curved-ends
(Double checked mine there - mine has an 18mm buckle, so if definitely the 1st, cheaper one)
You might need to register with them to see that. I got mine off SC for a tenner... so might be worth a WTB. Bry had some of these style for sale for £15 or so which I did try - but it just wouldn't squeeze in tight enough to let the springbars reach their holes. The Cousins ones are a tight fit, but they DO fit. Fit to the case is pretty perfect really.