Thanks, that is really useful to know. Had seen these but was not sure of fit.I still have my Raydyot mirrors from over 40 yrs ago ( bought 1982) and they fit ok on the Wingard door mirrors. I’ve had a look on eBay and there are a few advertised -Raydyot Classic seems good search wording. Otherwise look for the sort that clipped onto the front wings. They were popular 50yrs ago and occasionally appear on eBay too.
Just spotted a pair of the wing-mounted sort: type Vintage Towing Mirrors and they should come up. Very 1960s/70s. ( I was there!)