Maurice,
because of the comparatively narrow width of your Eriba then legally possibly no, but you do not want to be entering a discussion with a nice police person or be arguing with somebody from your insurance company.
Common sense says buy them and use them. You will be amazed at the difference when you set them up.
Millenco Aero are arguably the best generic mirrors available with flat or convex lens, choice up to you. Sometimes a faff to fit, especially with some VAG models, different "feet" are available to help.
I've recently bought some EMUK after a year long search for a pair. These are custom made to fit your specific vehicle but expensive, at about £105 a par imported from Germany.

Colin

Lots of discussion if you look for "Towing Mirrors" on the search engine.

Here's a good one :- Towing mirrors

Randa