General Zod
Banned
For most of the 30s Poland's main ally was Germany.
WHAT ???
I'd think this would be a bit of a disaster and allow Chamberlain's policy to fully work.
Chamblerlain's policy was "let Hitler exaust himself killing Stalin for us", not "let's attack Hitler when we are ready", therefore it would suit a smart Hitler's objectives perfectly.
They wouldn't get any such treaty with Poland, Poland was the line in the sand and Poland itself wouldn't go for it.
If Hitler doesn't invade rump Czechoslovakia, appeasement policy remains fully valid. As such, Poland never becomes the line in the sand and Britain never give it any garantee, since Britain always had very grave doubts about the wisdom of giving West Prussia, Danzig, and Upper Silesia to Poland in the first place. Therefore, they are not going to fight for Poland's very questionable Versailles territorial integrity. They shall gladly pursue a Munich-like agreement on the Corridor and Upper Silesia. If Poland doesn't accept it, London shall gladly let them hang themselves to German and Russian rope. Especially if Hitler does something smart to piant the bullheaded Poles let the frist shot, say by organizing an irredentist German takeover of Danzig, which the poles go guns blzing to suppress.
Also they couldn't really bother France or else Britain would be drawn in.
France isn't going to pick a fight over Poland if Britain shall not lead, or if they do, it is a wholly symbolic phony war show that winds down to a white peace in a few weeks or months. When this happens, Germany has no more reason to attack France, so detente with the Western powers may go into full swing.
From around 1941 the UK would hit Germany as soon as the time was right- and this UK would be fully prepared for war.
But they would not. The British ruling elite had NO intention of purposefully attacking Hitler if he pursued his objectives of expansion in Central and Eastern Europe by "acceptable" means (they had already chalked it away as Germany's economic turf) and NO intention whatsoever of getting involved in the Nazi-Soviet feud on Stalin's side.