Aircraft roundels originated with the French Tricolore cockade. Concentric circles are used in many many country's roundels, and are far from anything particularly British.
It's as if I said "The American flag (composed of stripes and a blue corner)" and you were to say "wait, that's not exclusively American"
Yes but, so what?
Which you can distinguish from all other roundels, by definition, or they wouldn't be useful things to have!
Aircraft roundels originated with the French Tricolore cockade. Concentric circles are used in many many country's roundels, and are far from anything particularly British.