Previously a CFI/HoT (not an FI(A)) would need to recomend that the supervisory restriction
be removed.
It didn't have the be CFI or HoT. It had to be an unrestricted instructor who was on the books of the flying school, who was nominated by the school to supervise restricted instructors. I wasn't aware that this had changed under EASA, since it no longer applies to me I hadn't read that section.
Still, no definitive text has been produced as to what is expected when an unrestricted instructor is supervising a restricted one. The AFI stuff simply doesn't apply to this rating, and the only AFI rating issued these days would be for microlights. There have been no accidents to take this to court to get a ruling, so the schools must be doing a pretty good job of interpreting the rules and mitigating the risk, even if that means that you are being supervised by someone who is at home. A bit like a junior doctor being left to it on a night shift with a consultant on call at home in bed.