First, I won't recommend any specific place, but give you guidance so you can find a place that appeals to you.
Can't say I had Chinese food much in London, but it is popular, and there is such a thing as "British Chinese" just like we have "American" Chinese, plus I have seen all types of regional Chinese places, dumpling and dim sum places, Bao, plus Viet and Thai places. There is a Chinatown in London, maybe start there.
For Indian, you will get many recommending Dishoom, they serve good food, authentic? many believe not, it is sort of a "cleaned up and tamed" version of Indian. I think you can eat cheaper, better, and not have to wait in line, by going to more of an old school place. You can go to any number of places in the Brick Lane area that will knock your socks off.
British Food: I'm looking here specifically for places that serve prime rib (rib of roast) plus Yorkshire pudding and the other traditional sides
Specifically what you are looking for is a Sunday Roast, served on Sundays, early afternoon. You will see a variety of meats offered, roasted potatoes, Yorkshire Pudding, and veg. Other than that, you will not see Yorkshire Pudding during the week commonly, but a restaurant that specializes in Roasts, will. For other traditional "British" dishes, a pub might suffice, I have found just about any Fuller's Pub serves above average food, but there are lots of independent gastropubs serving great food. Avoid the big pub chains (Weatherspoons and Stonegate) I even find the Green King pubs vary quite a bit, but usually to the worse. For any of these chains, the name of the chain is usually not in the name of the pub, but is clear on the website.
For all of the food choices you mention a great resource is TimeOut. Search for "TimeOut London Chinese" and you get: https://www.timeout.com/london/restaurants/londons-best-chinese-restaurants Updated as of January, same with Indian, same with Sunday roasts, same with Pub Food, Fish and Chips, and I suppose "traditional" British restaurants...didn't look though. Just watch the date the article was updated, something a couple years ols is probably outdated.