Season 1, Episode 5
Receptionist Elaine is coming on to Computer Tech Al:
They start snogging.
My question: What is a “non”?
Either a nonce, meaning a bit of a doofus, or a non-starter. Probably a nonce.
Thank you. Now I can sleep tonight. 
It’s not likely to be nonce, which in BrE slang is a sexual deviant, particularly a child abuser.
Could it be nong, a foolish or stupid person? The OED has it marked as Australian and New Zealand slang, but in recent decades a fair amount of Australian slang has made its way into informal BrE through the influence of Australian TV soaps, and Elaine and Al are of the generation that would have picked up and used that slang.
Nor would Al be likely to say “i was a deviant once, but I’m not anymore,” especially since we’ve also never seen any evidence of it.
The above transcript was taken off the Internet, BTW. It’s not my work.
It may not be nonce, but I have never heard it used that way. For most of my life it’s just been a silly name for idiots, which I figured was short for ‘nonsense’.
I’m not a pro with British accents, but couldn’t it be “nun”, as in prudish or inexperienced? To my American ears, I hear the “u” sound more than an “o” sound.
Hardly, if it’s being used of a man. “Non-starter” sounds more likely (=too shy to ask her out?)
Yeah, if non itself isn’t a term already, then the context she uses it in seems to mean “non-starter” or “non-person” or something like that. Something she would never consider.
For more context from the episode, Al has been impressing Elaine by not only fixing her computer and printer but also when he smooooovely puts his hand on hers as they work her mouse in unison. Then later in the pub she learns he’s into the same cool music she is in to.
So basically, she never thought he was cool boyfriend material, now she does.
My own impression is that the “sexual deviant/child offender” sense is the dominant one, but I have to admit that this is largely based on seeing it used in British police/prison TV shows . The Oxford English Dictionary doesn’t even know about the “idiot” sense; they only offer this one. They have quotations exemplifying this use going back to 1970.
Macquarie, the standard dictionary for Australian English, also only gives the “child sex offender” sense, and notes that it’s “chiefly British colloquial”.
You’ve led a charmed and sheltered life! Or haven’t been watching the right Police dramas. Nonce is what paedophiles get called in prison. Unfortunately I have close-ish knowledge of this, as a friend recently spent time in prison, and was upset when she discovered she was sharing a cell with ‘a nonce’.
So I think it’s safe to assume the writers of the nice, gentle, family drama Doc Martin would have picked another word.
I guess I was just missing the context. I feel strange now, like I’m in topsy turvy land.
Be grateful your mind is pure and unsullied by the nasties of this world.
Doc Martin’s patients Drew Peacock, Ben Twilly and Dan Gleebles (and his wife Jan) might think differently.
Since I started hearing those, I’ve always paid close attention whenever he calls patients into the surgery. 
This link should drop you right at the part where this conversation takes place for those who would rather hear the voice than rely on a transcript.
Would anyone else actually appreciate having Doc Martin as their general practitioner/primary care physician? No nonsense but at the same time, really excellent diagnostic skills. Though he would be frank about telling me to lose weight.
Dawk?
Sorry, thought it said Don Martin Question.
Unfortunately not available for the UK! And it’s been taken down from Dailymotion, which is my usual alternative
If you have Opera, the free built in VPN set to “Americas” works.
And it’s definitely short for “nonstarter”