I think British should get a 20% hp buff on heavy tanks at least. Or may be they could make all factory units nation-special too. Anyways, british can't be competitive neither with france on loot speed nor chinese on special unit nor greece on economy and still worse in overall. Not saying about comparison to romans. If they decide to stay with just loot bonus and no other perks it should be 20% like France has on army speed up. Among other perks, I'd want them to consider twice faster tactics and generals building times. It could make this nation desirable for attackers as it planned to be