UK based chef here and I have Historic Heston. While it is super interesting from a food history perspective, the recipes and cooking are far more suited to a professional environment. The dishes are pretty far removed from their beginnings.
Great British Bakes fits your criteria on the baking side. Its all classic recipes placed in their historic context.
New British Classics by Gary Rhodes.
The River Cottage books by Hugh Fearnley-Whittingstall.
British Regional Food: In Search of Best British Food Today by Mark Hix.
The Ritz London: The Cookbook.
The Hand & Flowers Cookbook by Tom Kerridge.
And don't sleep on Great British Chefs website their recipes are interesting, well tested and more sophisticated than the average content you'd get from a more home cook targeted site.
Not sure about a class, but this is supposed to be a good book on Amazon.
I love using lentils/beans/legumes in dishes.
Lentils are great for stews, dals, and soups. Beans are great for chili, soups, or even a simple bean salad (white beans, lemon, herbs, olive oil, salt). Chickpeas for hummus, soups, pasta dishes. Ottolenghi's book Plenty really opened my eyes into vegetarian cuisine, highly recommend: https://www.amazon.com/Plenty-Vibrant-Vegetable-Recipes-Ottolenghi-ebook/dp/B005CRY2O6/ref=sr_1_1?dchild=1&keywords=ottolenghi+plenty&qid=1602016535&s=digital-text&sr=1-1
It's expensive, but I really enjoy Notes from The Larder. It's as much a book of essays as it is a recipe book. I have the hard copy, and I revisit it often.
The Bread Ahead Cookbook. Not so much pie, but lots of bread/pastries/doughnuts (of which I've praised in other threads because they're amazing.) If you've been/or will go to the Borough Market in London, they're the big bread shop that sells their stuff and smells amazing.