Further to @paneuropaul ’s recent note about one of these popping up on ebay, it seems there’s now an aftermarket option which look pretty darn good. Spotted on the samba… https://www.evamclassic.com/products/view/Knipperlicht-schakelaar-NIEUW-T2-1973-1974-211-953-509-HR
Also there’s the 3D printed repair parts option, someone on here uploaded the details/ maybe shared file link on here previously.