Thermals.

I find Damart are good but more expensive than M&S, the latter are my first choice for that reason and I also recommend their Heatgen ones. I have some merino wool long johns from Rohan, bought warily because in the past I have found wool itchy next to the skin. But they are definitely not! Pricey though.

ClaretJan might be worth going up a size to your normal size if you want them less close fitting.

Silk is ok if you are being active, but not so good if you are sitting around. I also recommended M&S Heatgen. Even better if you can afford it, merino wool. (retired outdoor worker here).

Wish I could help you but I have trouble finding vests! I used to buy M&S ones but they all seem to be too tight and clingy now and feel very uncomfortable. I hate anything that makes me feel constrained!

I have one silk vest from Patra. It wasn't cheap, but it is the one I wear most when the weather gets colder.
www.patra.com/?MC=PP10&msclkid=a8efe8f84fa71e5c1d0b895b30281dc9

I have had three Damart vests for about 6/7yrs now and they have kept well I have invested in two more this year with long sleeves I know they are a bit more expensive but well worth it ,

I swear by M&S Heatgen thermal long sleeved vests. They come in all sorts of colours and some are longer in the body. Quite often they are reduced in the sales - usually because the colour was not very popular. I acquired a bright yellow one that way - its hideous but so warm that I don't care.

The best thing I’ve ever had was a merino vest from the Spirts shop.

I have worn M & S thermal tops and leggings for years, and they are comfortable, warm and easy to wear under lighter clothes.

When I went to China I was persuaded (!) to buy a set of silk thermal underwear. It felt nice but it didn’t keep me warm?

Marks and Spencer might be worth a try. I’ve got some thermal tops from them and they’re soft, warm and cosy. You might get thermal gloves from one of the outdoor clothing suppliers.

I bought some Anyday thermal tops from John Lewis, very comfy and warm.

Damart?

I find some thermal vests a bit irritating. Having been without power for a couple of days I’ve been living in a very ancient thermal vest that isn’t prickly and may have to be surgically removed if I don’t take it off soon ( power now back on) but I don’t remember where I got it from. I’m thinking of buying a silk vest which I assume would be very warm in winter but cooling in summer?