Dear 9,3x64 and All. Thank you for understanding that my comments were a bit provocative, but not on the wrong side of the meaning, and I do praise your sense of humour!
Unless referring to nationality each time one mentions a European calibre e.g. a British one, a German one, an Swedish one, etc. I think that on a wider European scale (including the British Isles of course) one should therefore refer to two distinct categories i.e. Imperial and Metric ones when talking about European calibres. However I do not intend to turn that mole hill issue into a mountain and things won't probably change!
Louis