Not really, no. As a policy, appeasement was based on two flawed premises: first, that it was Nazi Germany's self-interest to avoid war, and second, that the Nazis recognized this fact. Ultimately, neither was true: the Nazi economy was based upon constant expansion and would have collapsed under its own weight without it. Even if this wasn't true, Hitler and those who surrounded him were largely zealots, and we're not above picking fights even when the odds were stacked against them.
The problem is, the writing was already on the wall by 1940. After Czechoslovakia, one could realistically back appeasement as a policy, since there was nothing concrete to prove that it wasn't going to work. Poland made this considerably harder. Britain's foreign policy could not coexist with Nazi Germany's as anything other than a interim solution, and Halifax knew it. From some accounts, Halifax was so disillusioned by the invasion of Poland he stopped entertaining the notion of a peace treaty then and there.
Not likely to happen, regardless. The U.S. is still going to get into a war with Japan. This is going to thrust them on the world stage in a significant way, even if not quite on the level as OTL. And Britain is still going to be facing most of the same problems it faced in OTL concerning its colonial holdings: increased anticolonial sentiment coinciding with a weakening economic outlook. The key difference here is that the weakened economy has more to do with prolonged cold war with Nazi Germany than the fallout of a very, very hot war with the same.
Which, again, is assuming that Germany's imperial aspirations don't ultimately conflict with Britain's, sparking the same level of destructive warfare that Halifax ineffectively sidestepped in 1940.