You'll impress them with the quality / originality of your writing, which you need
samples of to get their attention and your foot in their door, in the first place. So yeah, there may be less reason to "live near L.A." until you've got the opportunity to pitch, etc, based on samples of what you have to offer (which lets say may take a year+ to create your sample(s)
Best to have the luxury of getting the ball rolling located where ever you already are.
A working pro may indeed need to have easy access to L.A. (or where ever the production center is in the UK) because once you're established you
will be taking meetings, pitching again and again, spur-of-the-moment changes, all the typical day-to-day that demands proximity. But that's
after you've had initial success via your samples.
As others more knowledgeable have said: First learn your craft.
I'm just a beginner too, but I'd float the idea that "craft" may be secondary to creativity and originality of your story?
If some producer wants a script polished or doctored, will they hire a newbie anyway (when L.A. is full of writers with track records and personal connections already)? Maybe not.
What you can best offer them as a
newbie is something
NEW. Your unique story or vision.
You need to hone the screenwriter's craft and skills so that they trust you can pull off the technical aspects, sure. But just as genre writing loves the STORY, and literary writing is more about style ... maybe breaking in as an unknown cares most upon STORY more than writing style of the blueprint screenplay.
Paint your movie story in their imaginations, make them want to SEE your movie (well ... make them drool to know how many movie-goers will want to buy tickets to SEE your movie) ...
But a screenplay isn't the end product there, not for them. Remember that crafting a screenplay isn't the same end-all-and-be-all as writing a novel is. Be good enough to not trip yourself up, be good enough to make them imagine what a helluva movie they could have!
Just me opinionating, of course.