Baz every day is a school day you cart be any way responsible for that I would of gone colour to colour if you don't like you said it go's against everything. Excellent video and well diagnosed
Every Mechanic and Auto Electrician (Me) has been caught with this style of thing, stickers on wrong or part with wrong label etc., the main thing is we learn from it and make the customer happy in the end, you achieved both so well done.
My biggest head scratcher was headlight washers on a mini inop. After hours, head scratching, a washer pump and an ecu later it turned out the bonnet switch was the issue....
Had a similar case once. Another garage had taken off and cleaned the DPF on a ford kuga 2.0 tdci. Came in with limp mode. Codes for differential pressure sensor. Could never make sense of the differential pressure I was reading on the diagnostic. Turns out the pipes to the differential pressure sensor were switched. One side of each pipe is smaller in diameter to the other side. And there is a small and big fit on the dpf metal pipe and differential sensor. So the natural thing there was to put small to small and big to big, but wrong! Switched the lines back and it was fixed. Real head scratcher!