skarpi, I know just what you mean. I have several friends like Doc Martin too. Also I was a nurse so I worked with several. I also have a friend -- possiblly more than one now I think about it -- like the mad Irishman in the episode in question.
I find the story lines in Doc Martin a bit ordinary but the characters a lot of fun. Also,of course, the scenery is wonderful.
Cheers, Joy