Another item on Finian Moore's wish list was to replace some of his chrome wheel nuts that had lost the dome on the top. I can only assume that it is held in place by that Haynes Manual favourite the "interference fit", otherwise known to normal folk as "rammed in effing tight". I doubt that once they have come off anything will keep them in place again, but I welcome your comments if you know otherwise.
I found a few spares languishing in the garage, got the worst of the corrosion off with Autosol my favourite metal polish and added them to his parcel.

Opel Manta A series chrome wheel nuts