I am sorry but I will have to disaggree with you there. It is very evident in 1945 that patches were worn which should not be worn.
If this is in England, why would an American wear a Canadian uniform? he is in their records as a Private. Was there a rule that a civilian had to wear their uniform to work with the unit? I have seen all kinds of civilian uniforms worn in England during the war. Judging from the caption, it looks as though this guy worked in England only.
I have seen tons of photos of guys - as you have too - showing odd badges and badges they should not be wearing and also badges that are missing. There are many reasons for this, supply being one. Even if he was working for another group, he was still in the unit as he is in the documents as being part of the unit as a Private. One would figure if he was a liaison of some sort or working for someone else, he would be an officer or at least be given NCO or officer status. There were tons of privates in the unit, many over the age of 35.