nr. 003 is British actor Tony Adams - who is credited on the IMDb but not given a character name. He was a popular actor in a well known soap opera in England.
Also below is a pictor of Tony Adams - again wearing glasses - from 1973 - in the cult TV series Doctor Who.
In the English language version, the two lines spoken by the nurse are dubbed by Suzy Kendall.
There is a "Gaetano Imbro" living in Ancona - I wonder if this is the same guy because he has only done one film (Lucertola)
I think the actors 001, 004, and 006 are English actors. They all look English and all there scenes were shot only in London. Also they look English/British, not European.