Avec plaisir! It is always interesting to me too, to explore the nuances of language.

Thank you, Wendy, for these so interesting precisions. ;-))

France - May I suggest: A guy who served ten years in prison for a casino robbery, or, (because we don't know if he has actually served the full ten years: A guy who was sentenced to ten years prison.

It is just a nuance of meaning: who'd been sentenced to ten years - doesn't necessarily mean that he has served any of his sentence. It indicates that he is possibly getting out earlier, before the 10 years are up or that he hasn't even begun to serve the sentence.

I would either write: who's served ten years (if he had served the full term, which we don't actually know) or / a guy who was sentenced to ten years prison (means - he has most likely served some if not all of the sentence - we find out in Unit 21 that he has just been released)