Hey Matt
I am a current student at Hallam and I can say the best things to revise for are aerodynamics, structures and propulsions. These are the main areas we study/ied there is a materials branch but unfortunately for myself is quite a new feature to Hallam so I am unsure what exactly they cover.
Other things we cover is CAD simulation, professional engineering standards, systems/ avionics and control.
the primary focus would be the aerodynamics and structures though as they seem to be the two modules that people have greatest difficulty with.
When starting to read up on stuff try to go for 'the basics' first as they ease you into the concepts first then work your way into the heavier mathematics.