As said before, tea (in London as well as the south coast, not just tthe north of England) was the evening meal. If a later meal was planned and friends were over, then it might be tea and cakes, but I wouldn't say that this kind of tea time was the rule. In boarding schools, evening tea was what we call dinner, and tea was served at breakfast and dinner. In fact, I had to get special permission (and pay extra) to get milk with meals, but that was soon after millk rations ended.

Schools at least also had a break at 11:00 am called "elevenses" which might have included a drink and a boiled sweet (candy).

Tea shops were perhaps more common then than now, and served crumpets, scones, and things I no longer remember. Bovril, Marmite, lemon curd?