Re: Double down?
@Cardinal - I admit, I inherited "double-down" from the American political channels.
However, along with what Frumious Bandersnatch says, if making an error is "down", then doubling 'up' on it is doubling down.
I largely agree with the rest of your post, (and I didn't downvote you)
Maybe I should stop using Americanisms... My bad. Have a nice day :-)