Yes, I know. But wouldn't the British chap's prior art make those lawsuits invalid retrospectively?

I don't know enough about even my own countries' legal systems, and certainly not about America's. So my question is: Supposed you got sued back then, had to pay, and now try to get the money back, because the patents the suit was based on were invalidated by prior art. Would that work? (Sorry, not a crypto-question at all, more like a legal one.)