The London Lounge

... delivers a masterclass in nonchalance

Would love to know what the coating fabric is third from the bottom.

So would I.
Looks like a very heavy large herringbone tweed. Probably 28 oz. or more. I have not seen anything like that recently. The closest thing would be a Gamekeepers Tweed from Johnstons of Elgin.

There are some handwoven Donegals I've seen in that scale of herringbone, that would be your best bet in my own opinion.