Not many games does Germany lose ALL it’s subs on Turn 1. Also, even if the UK takes Cpr on Turn 1, instead of taking a more rich target like Java or Sumatra(not the best UK strategy), that’s 36 IPC’s to spend on Turn 2. So, instead of buying 9 Inf, 1 Art. You’re buying 8 Inf, 2 Arm. In that scenario, that’s 24 Inf, 2 Arm, 6 FTR’s, 1 Tac defending against SeaLion. Odds calculator says Germany wins : 67.2% of the time. So in that scenario, you’re only decreasing the odds of Germany winning by : 2.3%. Also by not building 4 Inf, 4 Art on Turn 1, if Germany invades Scotland w/3 Inf 3 Art on Turn 2, then decides NOT to SeaLion, you’ll only have Inf to counter-attack. My recommendation is UK builds 4 Inf, 4 Art on Turn 1, so as to have the max counter-attack force possible, not only against Scotland but future turns against Germany.
EVEN if the UK has 40 IPC’s to spend(highly unlikely). That’s 3 Arm, 7 Inf on Turn 2. Leaving 23 Inf, 4 Arm, 6 FTR’s, 1 Tac defending. Odds calculator says Germany still wins : 56.3% of the time. Now of course, most good Axis players won’t risk SeaLion at this point but my point is, it’s still possible. AND, if the UK player is diverting all of it’s forces(i.e. all airforce) to the defense of the UK, then the Italian player is loving life). If the Axis see this Allied move on Turn 1(i.e. the Brit trans from SZ98, load up 2 French Inf and assuming all German subs die on Turn 1), then of course on Germany’s Turn 2, they don’t build 7 Transports but can still land in Scotland if they want and divert their attention over to Russia, still while threatening SeaLion and keeping the Brits down. Or, just divert all of their attention over to Russia.