My main curiosity stems from the Canadians taking Juno, with the British on either side. It seems more beneficial to have a larger landing area for the British, that way if they needed more support then they could send them over from the other one, but with Canada in between they would have to ask the Canadians to do it, and go through another armies chain of command, but they obviously didnt do that. why not?
For the D-Day landings there was one Canadian infantry division (3rd) with an attached armored brigade (2nd). It was not acting as an independent national command but was fully integrated into British I Corps, and subject to the commands of British 2nd Army. No permission from higher Canadian headquarters would be required for tactical disposition of the Cdn troops involved or to move British troops into or through the Canadian landing zone. When more Canadian troops were landed, II Canadian Corps was activated in early July, but still under the command of 2nd British Army. 1st Canadian Army did not become operational until late July of 1944 and was under the command of British 21st Army Group. Although Canadian in name, 1st Canadian Army was a multinational force with 1st British Corps and 2nd Canadian Corps as it's main components although other British Corps, the Polish Armored division and even American troops were under it's command at various times.
TLDR; Canadian formations, although national in make up were fully integrated into the command structure of the British Army and operated as a component of it.