I have seen this claimed in several Youtube videos and sensantionalist media, yet I have not come across British troops landing on Norwegian soil, only Scottish mercenaries in Swedish employment and maritime border violations during WW2.
What period of time are you thinking of?
Britain did fight the allied forces of Denmark and Norway during the Napoleonic wars, though the Battle of Copenhagen (1801) and the later bombardment of Copenhagen (in 1807, during the so-called Gunboat War) took place in Denmark. British troops were also part of the Allied expeditionary force sent to Norway after the German invasion of that country in 1940.
Prior to the German invasion, the British boarded the German ship Altmark while at sea in Norwegian territory, rescuing about 300 Allied POWs, which is a technical violation of Norwegian territory but not an "invasion."