Every Y1 class is different. There is no 'right or wrong' way to teach. School leaders, in consultation with the class teachers, will plan accordingly to meet the cohort needs. The difference between schools even in the same town can vary a lot.
I teach Y1 and every class I get are different from the last. I have never had two classes the same. 2 years ago I had a class of Y1s who needed to learn through play throughout much of their time in Y1. Yet last year the class were ready to ditch learning through play by october half term (mornings - afternoons was still very much a carousel).
You should find in the majority of Y1 classes that children are more structured in a morning than an afternoon. My class are split into 5 groups - 2 are adult-led, the rest independent BUT those 3 groups could be a simple Bingo game, match activity, handwriting practice in sand or paint etc and a computer activity. They would be told what activities are planned and they 'choose' which ones they tackle first. By the end of the week, 99% of children have had a go with every activity, some would spend longer on it and others would try it our several times over. Sometimes a direct activity for independent learning could be to role-play a doctor's surgery or to write a book about themselves.
'Work' to a five year old could simply mean being told to sit at a table or within an area and complete an activity. It' isn't necessarily sitting at a table doing the three R's. Our aim this half term is to increase their stamina, patience and resilience whilst doing a direct activity for about 10-15 minutes and the biggest aim is to improve their independence skills so they ARE ready to take on more formal reading and writing activities within lessons.
My 5 year old comes homes and tells me he's had a 'work day' or 'done work all day'. When quizzed, one of his jobs might be to draw his family, colour in a robot (some of the things he has said this week!) and play with shapes at their tables.