I dunno about the Brit PPL but we have to do 5 hours of instrument flying, this is compass turns and unsual attitudes, we did not ahve to do any Radio Nav stuff, that is covered in your IR training (should you do it) post PPL.
Your own headset is a good idea, sometime school headsets can be a bit crappy, make sure its a good one though, do some research. if you can plug it in and try it out, especially with the engine running, listen to ATIS, do a radio check and make sure the Mic is ok.