Norway was captured by Germany during WWII, and been liberated from Germany after Karl Dönitz signed the surrender treaty with the Allies. But there were some chances for Allies to create an assistant for Soviet on the eastern front by attack Norway.
Norway was a very strategic location for the Third Reich, a place provided submarine bases nearby the supply chain from Britain to Murmansk. And protect Sweden from the invasion of allies.
So the Allies had a lot of chances to take Norway back while the German army was focus on the Russians. And this might lead to a new front line for Germany in the North. And this front line will be hard for Germany to supply because of the advantage of the Allies’ surface navy power. And this is an invasion that Britain can do it on its own.
So why didn't Allies use an amphibious invasion to control such a strategic place.