I feel sure it was the Guardian subs desk rather than you who made the terrible, nay egregious, error in your column today.
But just in case....
A mantel of domesticity is a shelf above the fireplace that you put cute china figurines of kittens on.
A mantle of domesticity on the other hand is probably the metaphorical item of clothing to which you wished to refer.
No, not at all, happy to help.