Speedbird
you only need a Class 2 for PPL - not such a big deal . The examiner will do a general exam, eye test inc colour vision, blood test, ECG (heart rate/rhythm) and a peak flow, which tests your lung strength.
Cost will be around £100 for initial, and it lasts 5 years if you're under 30.
Anyone who is basically healthy will pass - but if you wear glasses check your prescription before shelling out - I think you need to be less than +/- 5 dioptres for your initial.
The only other thing - if you're going to go on to commercial flying, get the class one straightaway - I ended up paying £100 for a class 2 so I could solo then going to Gatwick for the class one about 3 months later...
Don't worry about it - I'm terrified of things medical but managed to get through it!
Cheers