A decent torpedo bomber is absolutely requisite to even beginning to take on the RN, and by decent I mean something with a single engine and an empty weight of under about 6 tons.
I'd say you could be more likely to do it if you made it so that it was the Germans rather than the British who took an early interest in carriers (maybe the British get overconfident about their battlewagons while the Germans, knowing they can't keep up, try desperately to find some other way to strike at them).
Edit:
If Scapa is too far away to attack how come Britain's first civilian casualty was killed in an air raid on the place?
I never said it was impossible, just that it wasn't easy, and it's not, it's further from Kirkwall (the biggest town in the archipelago) to Kopervik (the nearest major town in Norway), than from London to Paris, Brussels or Amsterdam. Also, only a couple of raids were made, indicating that it wasn't a worthwhile target.