Re: The war is over, the empire is gone
If one looks at the costs of WW1 and WW2, it's pretty clear that Britain could have handled either one of the wars by itself, but not both. At the end of WW1, there were strong voices suggesting not to push all fault for the war, and massive war reparation payments on Germany, for various reasons, including to avoid the rise of characters like Hitler.
While it's debatable if a Hitler would have emerged had the Versailles Treaty been less harsh, and while one can't "blame" WW2 on those who penned the Treaty's key provisions -- i.e. France and England -- they certainly had a hand in forging one of the key links that made WW2 possible.
So perhaps one might say, "You don't have to thank us. We broke it, so we did our best to fix it as a matter of principle."