Sealion is not the way to go.
1. Odds not in your favor: A. survives: 22% D. survives: 73%
2. If you fail, you have just lost the game.
3. If you succeed, you will have lost more units than the money you will get from UK, while letting Russia get ahead in the builds.
4. You will lose Gbr against the UK or US counterattacks. If you retake it, you will lose it again.
According to odds and some of my calculations, this strategy will win you the game less than 20% of the time.