OK, Doc Martin is not written to be a comedy. It's a comedy/drama.
This Yank, as you so off-handedly call us, thinks the success of this show is its ability to laugh at itself by creating characters that are unusually passionate and most often over-the-top unstable. The pharmacist (chemist) wears a neck brace with no explanation as to why. All the doorways in the town are too low so that Martin is often bumping his head. His brutal honesty is so off-the-wall as to force everyone he encounters to be put in their place. How sad it would be if we could not laugh at these ridiculous encounters. How cleaver of the writers to weave into each story something earthy and realistic to balance the foolery.
When will Doc Martin return to our air waves? I have turned a lot of people on to it and they, as well as I, are anticipating more.