Rigby 275 / Kynoch 7X57 / Czechoslovakian 7X57 - Questions

This calibre was probably the low point in the British ammunition world, Rigby, a quality rifle maker but a small rifle maker, lacking the resources to R&D a new calibre from scratch tried to clone an existing calibre and pretend it was their own. They fooled nobody, why did they not just call it what it was and keep their dignity? Answer, because the word bespoke still cut some ice in some quarters