The German bombers could reach ALL the airbases in the UK as soon as the war broke out in 1939. The first time the Spitfire drew blood was over Edinburgh (Scotland) in 1939.
However their escorts couldn't....
Which is another point of how silly the whole affair was.
The crossing from France to the east coast is about 6.000 km. If you want to hit a target on the west coast, you would have to cross a hostile territory some odd 4000 km. Then return

Sorry Fritzies, what was not even do-able over the 30 km of the English channel is definately not possible over the Atlantic.
As a sidenote, German bombers did occasionally venture over Iceland with hit & run tactics. Sometimes there was success, sometimes they got shot down. My mother witnessed a chase when she was a kid - the German came low over the farm at full speed, and quickly after it, 2 American fighters.
The distance there (From bases in Mid-Norway) would be some odd 1.400 km, never under 1.000 km.