This guy has had this advert on eBay for a long time. May have something
https://www.ebay.co.uk/itm/YELLOW-M...898968?hash=item4d79ea96d8:g:z8UAAOSwEW9aiz68
Check all his items as he has a few sizes listed
Or the usual suspects, great exportations, hes tractec,
https://tractec.grouphes.com/matbro-parts-spares
And of course our resident expert @ACEngineering
I have one I think, I kept it when I scrapped mine, if you want measurements or photos just say.