Im Ajay.
The campus is great, you will mostly be at markeaton street campus and britannia mill.
It will proably vary but in my year there are about 30 people, i think i heard one of the lecturers saying there were more applicants this year though. The lab rooms arent big enought for loads of people so you will be split into smaller groups so i wouldnt worry about class size.
The maths isnt too hard in first semester, if youve done AS physics and/or A level maths you will be fine.
Any other questions?