When my DS went to school in the UK for his reception year there were 33 children in the class, one teacher and one TA.
Now he is in a class of ten children with two teachers and two TA's.(Bilingual school) In public schools here the max number of kids is 16-18 with one teacher and one TA.
I think this makes a huge difference in the pressure to get kids reading and writing. Although they are grouped by age generally, his work is set individually for language and maths. Science, French, sport music and History tend to be more of a group activity. Kids move up or down and it's quite normal.
School hours are 8-12 every day, with two afternoons 2-4. Within that time they still manage swimming lessons and sports. Homework is full on though - DS gets 2 hours of homework for his midweek afternoon off. The other afternoon is generally supposed to be time to do a personal activity - specific musical instrument, martial art, sports team etc.
Kindergarten is about making cakes, walking in the woods, collecting firewood and making campfires, learning to walk to school unaccompanied, learning to sit still and singing songs. 
However the school he is in does teach reading/writing earlier than public schools and there are now higher levels of local parents putting their kids in the school because they don't feel they are challenged enough by the KG and are bored.