Whether they are right to be nonchalant about this is up for you all to debate. But it is important to note that the War Office isn’t very scared.I will stress this though. While it’s an unfortunate development The War Office is mostly unfazed and unworried with the grand American offensive. They expect the Canadians to lose ground but the Office has devised a lot of plans to rapidly gain it back. They also know (for the most part) that their men are better trained, and that their naval superiority isn’t going anywhere.
(The same cant be said for parliament though. Most Liberals and Irish nationalists are getting jittery. This is why Spencer had Thompson removed from the premiership in Canada. Parliament wants to see results. Generals and military advisors are trying to calm them but only good news from the front can really do that.)