As well as a flight computer and a kneeboard you will need:
1/2 million scale CAA aeronautical map
VFR flight guide
Checklist for the relevant aircraft
Ruler calibrated in nautical miles
Protractor
Logbook
Selection of OHP pens and china-graph pencils
Books covering the PPL exam subjects (I used The Private Pilot's Licence Course books 1-5 by Jeremy Pratt as published by AFE)
Your flying club would be the best source of advice for items required though and they might sell you a 'complete set' of everything you need to pass your PPL.
I mostly use the pilot's shop Transair for my flying equipment.