Aloha, I currently study Natural Sciences at UCL, and I do 2/3 of the modules which the pure physicists do.
Personally I think the Physics department is fantastic. The lectures are brilliant, they don't glaze over any topics; you get a deep understanding of the subject rather than just knowing and using the formulae. In terms of admin, they are very friendly and helpful people. This is all compared to the Chemistry department, where the other half of my course is taught- the Physics department definitely run their courses better.
In terms of content, I'm in my second term of my first year, and here is what the people doing pure physics have each week:
4 hours of thermal physics lectures
4 hours of waves, optics and acoustics lectures
4 hours of mathematical methods lectures
3-4 hours of tutorials (groups of around 10) where a set of problems are solved
In addition, there are a couple of short essays and a communication project.
I will say the emphasis placed on maths is strong. I looked at the topics covered in the first year, most of which were covered by maths or further maths A-level, and thought "well this'll be easy", but the questions are a LOT harder and you will need a very, very good understanding of where the equations come from to do well in the exams. I found an equivalent 1st year maths paper on the Cambridge University website, and that is much more like an A-level paper.