I used to transport my Greeves to scrambles on an M20 outfit with plank and did buy a sidecar and fittings intending to fit it.
but decided that riding an outfit one-armed was asking a bit much. Besides, they don't lean into corners, can't filter and so I might as well drive around in the rain in an MX5 with the roof down.
I sold the sidecar to a chap who came 200 miles for it. He refurbed it and fitted it to his Lambretta. Nice job he made of it.