Hi Julie
It’s nothing to much to worry about to be honest and I can’t imagine anyone getting pulled up and smacked on the back of the hand for it and if you get Halfords to take it out before hand-back no one is the wiser.
I put my car in for its first service last week and while driving home I noticed the mechanic had pulled the power supply out of my dashcam and I wouldn’t be too pleased had something happened on my way home before realizing it needed reconnecting. They don’t like the ideal of being spied upon which is fair enough but they could have remembered to reconnect it before handing it back.
Just another thing about dash cams is about 2 month after getting my current car someone went into the back of me smashing the bumper in mean the car was off the road for a couple of weeks and guess what RSA asked me first thing on notifying them “don’t suppose you got any dash cam footage” and as it happened I didn’t because at the time I had not got around to refitting the cameras from my previous car but goes to show the insurance people like you to have them.