My family are Scottish. We moved to England when I was a child but continued the same pattern of meals.
Breakfast - cereal (Rice Krispies, sugar available if wanted, full-cream milk), white bread toasted and lavishly spread with salted butter (marmalade available too), instant coffee
Lunch - school dinner - often extremely stodgy. Pastry and chips often featured. There was always a pudding - e.g. rice pudding, semolina, chocolate sponge pudding, steamed jam roll, something involving pastry.
Evening meal - Scottish high tea. Main course might be a pie from the butchers, home-made chips, baked beans (or tinned pasta). On other days it would be a quiche from M&S with salad (but probably chips as well). We wouldn't often have had something like shepherd's pie on a weekday as Mum didn't have time to make it in term-time. On the table would also be bread, butter, jam and some sort of cake or biscuits. We'd wash all this down with tea.
To be honest, it's a miracle we're still here, and yet my Dad lived to 89 (died last year) and my Mum is still with us at 91, and not doing badly at all for her age. My brother and I are in reasonably good health. He is now a pescetarian/near vegan. None of us eat the way we did in the 1970s. I think the high tea went west when Mum retired from teaching and had more time to cook properly. The saving grace of our diet was that we always had lots of vegetables and fairly often had pulses and fish.