In my experience everyone in England does cookouts and grills outside, but wouldn't know proper bbq if it bit them
I'd still call cookouts and grilling bbq though, so it is confusing!
Growing up in America, there was a distinction between throwing some hamburgers and hotdogs on the grill and having proper bbq, smoked brisket or pork or ribs or whatever.
Either way, the structure is different. In England I've had my in-laws version of a bbq and more casual beach bbqs with friends. My in-laws normally do burgers, sausages and chicken wings served with green salad, garlic bread, and maybe some boiled potatoes or a really light potato salad. No buns, no sauces. It is good, but it took a lot of getting used to for me.
Casual beach bbqs I've been to have been burgers and sausages cooked on disposable grills, buns and sauce, but pretty much no side dishes or anything involving plates and cutlery, possibly with a side serving of food poisoning. Everyone brings their own meat and they always forget that it takes half an hour the for the disposable grill to heat up. Half the time the grills flip over in the sand or you drop something. Still good fun
Growing up there were different levels of bbq-
cheapo burgers and hot dogs- this is the bare minimum, served with buns and condiments and maybe side dishes, but maybe not. Easy thing to do for a camping trip or something casual, can also be a free thing you could find in a grocery store parking lot or a park or church community event, may include pot luck sides depending on what sort of event it is.
burgers, hot dogs, chicken, brats, steaks, kebabs - it all branches out and side dishes include potato salad, baked beans, salad, chips, veggies, coleslaw, roasted corn on the cob, etc. There is a huge variety and you can run all the way to fancy fancy, more what people do at home when they have a bit of planning time or are having people over for dinner
proper smoked bbq - top of the food chain for sure! Properly smoked meat, (and of course debate over how to do it properly and what sort of sauce is acceptable!) baked beans, coleslaw, corn bread, greens... mmmm.