Teachers/TA KS3- How much ground typically covered in a lesson?

[whatevernext1976]

We're moving back to the UK in the summer and I'm preparing my 12 years old by going through some of the UK curriculum. In a typical History lesson, how much time would be spent on a Unit? For example, we've been looking at the Black Death for History and Urbanisation in Geography. How many 50 minutes lessons would you usually assign to a topic before moving on?

It is 24 years since I left school and finding it hard to remember and trying to gauge if I'm going into too much detail or not enough.

DD, also 12, seems to spend roughly half a term (approx 6 weeks) on a topic before moving on. Think she has 3 lessons per fortnight for most subjects.