this debate could go any number of ways.
For me personally i find the following won up the battle of britain -
RADAR
Spitfire
Hurricane
109's only having enough fuel for 20 mins combat over england
HE111's not having escorts all the way to targets and back
Our pilots getting shot down being able to get another plane and fight, the luftwaffe on the other hand become POW
Piss poor desicions by the german high command regarding targets
"Spotters" of the home guard along the coast
limey pride and attitude
Those damn nice strawberries during the summer of 40 and the great home baked bread, cracking i tell the!!
Pilots from all nations even those not in the war yet, comnig to our iad and fighting for the RAF.
luck