Natural shoulder vintage Ivy jacket.
English Plain point shirt.
Flatfronts that sit on the natural waist worn short in the leg by European standards.
English Plain toe Oxfords.
Lambswool knitwear in muted shades.

Totally Ivy. Totally Brooksy. Totally East Coast.

... And only the shoulderline is American.

Subtle mixing still:  Clarks' English-made chukka boots with Paul Stuart Italian-made cords.  Grenfell, Bill's and Sebago.

B.D. Baggie - now mostly Chinese?

Of course, I'm wearing mainly Italian footwear nowadays, Astorflex being kind to my ancient feet.

And did those ancient feet in ancient times etc.?

Baggies - Italian owned I believe, possibly made there or as you say, more likely China. I’ve not owned once since the Russell Street days. John was very dismissive of them when Chiltern St first opened & I asked about them, so I was faintly surprised when they got them back in again.

I’m currently hankering for Scottish knitwear, some donegal tweed trousers, some grey flannel trousers and a couple of pairs of Cordings heavy-weight corduroy trousers. Plus ideally american-made flannel shirts with a decent collar roll - the lands-end versions are just too pathetic on the collar. I’ve two pairs of shoes at the top of my list before I buy any of that lot however. As they say in game of thrones Winter is coming and it’s cheaper to buy lambswool or cashmere than heating oil at present.

Ross Russell suggested that Miles Davis was wearing English clothing by the time 'Birth Of The Cool' was released: tweed suits for instance (okay, most likely of some Celtic origin).  Perhaps the alleged Paul Stuart connection cropped up later.  Anyway, Miles liked his schmutter. 
I'm beginning to slightly move away from some of the old American names.  The USA-made Bean chinos I bought a while ago are all right but too obviously poly/cotton.  Those recommended by Uncle Ian are quite a bit better, I think. 
Jackets - the Stanley Blacker Harris Tweed has proved disappointing whereas the Norm Thompson is acceptable.  But - Ivy or not - I have a yearning for more Donegal tweed else 'Thorn Proof'.
Perhaps this thread should be retitled: 'British: Might This Be The Way To Move Forward?'

We could probably compile a list: beginning with A&S, moving onto, say, Cordings and Grenfell...  Not to mention the Scottish and Irish knitwear fancied and favoured by our American cousins.

A number of trad USA outfitters still stock UK made products. Often they're own labelled but at a guess Press stocks items made by Alan Paine, Corgi, Pantherella and Luke Eyres.

(I might be wrong about Eyres). Add to this Barbour, Grenfell and Chrysallis out of Northamptonshire. They also have cashmere from Johnstons of Elgin.

The Irish poplin ties are most likely Atkinsons but adapted to be slightly narrower.

The Andover Shop sells British made Seaward and Stearn shirts and a shed load of classic British toiletries too.

Ben Silver stocks Crockett. Great shoes. And Draper slippers and Ettinger leather goods

O" Connols also has some British brands.

It's funny that some of these once ubiquitous UK brands are now more visible oversees than at home. I blame the leisure wear chaps.

Does anyone rate Margaret Howell?