From late October to late March, weekday lessons run from 10 am to 6 pm UK time. From late March to late October, when the UK is on British Summer Time, they run from 11 am to 7 pm. A child who finishes school at 3:15 can come home, have a snack and a short rest, and still start a 30-minute lesson at 4:30 or 5 pm.
In December, Maghrib in London is just before 4 pm, so a winter after-school lesson comes after Maghrib and before dinner. In June and July, Maghrib is after 9 pm and lessons end by 7, so the lesson never runs into it. Lessons in the morning or early afternoon suit adults who work shifts, parents at home with younger children and anyone on a day off.
At the weekend, lessons run from 5 am to 5 pm in winter and from 6 am to 6 pm in summer. A Saturday morning lesson after breakfast is easy to keep, and leaves the afternoon free. In the coming years Ramadan falls in winter, when iftar in London is between about 4:30 and 6 pm. An afternoon lesson that ends before iftar works, or you can move to a weekend morning for the month.
Most UK primary and secondary schools finish between 3 pm and 3:30 pm. Weekend: Saturday and Sunday.