Confirm that the Class 2 medical does not involve needles. It does involve a urine test, and increasingly as you age, an ECG (every year after 50). The ECG is painless but it can hurt pulling the self-adhesive electrodes off!
The Class 2 is more expensive than the GP sign-off, but shop around - I pay £90 including ECG.
If you're as young as the OP the Class 2 is infrequent anyway (5 years? can't remember)