I am aware that the medical is different
You are quite right. For the NPPL all that is needed is a certificate from your GP saying, in essence, that he is NOT AWARE of any medical matters which might make you unfit to fly - very negative. Many GP's will complete it without carrying out any examination at all.
A JAR class 2 has to be done by an AME , and does involve a thorough examination, including vision, urine, haemoglobin, BP, ECG etc etc.
A much more positive assessment of your physical condition.