It is not really an issue since Russia can land up to 2 ftrs on London before G goes.
Any Allied player that sees a bid of 1 trn to sz 5 and does not land at least 1 Russian ftr on London is asking to get diced by Germany.
London should have at least: 2 inf, 1 rt, 1 arm, 3 ftrs, 1 bom
(bom can even be taken in the first wave of casualties)
With no aa hits for Ger, UK wins about 80% here.
With 4 ftrs, it is up to about 95%.