Very many thanks to Lenny and FOCA for the replies.
Now I have something to go on and the years and car type to look for.
I may have seen one of these today on an accident damaged car. Looked like an " Artillery Wheel " had five studs
and the tire ( about 135 size in width ) was clearly marked as " Spare Tyre " in large lettering.
Many thanks again for all the replies, Pauline.