Re: Hard cases
"I think that, if it is five years or more, you get the right to stay permanently anyway."
there have been at least two cases reported in the press of EU people applying to stay as a precaution. In spite of living here for many, many years they have been told they don't have the "right" documentary material for the process.
https://www.theguardian.com/uk-news/2016/dec/29/home-office-reform-permanent-residency-application-process-eu-nationals
https://www.theguardian.com/uk-news/2016/dec/29/home-office-reform-permanent-residency-application-process-eu-nationals