Tories Hold Sleaford Comfortably In By-Election.

The Tories held Sleaford yesterday and one must assume that this was an easy victory after the parliamentary vote the night before.
There was consolation for Ukip, who came second beating Lib Dems into third place and Labour into FOURTH!
As I have written repeatedly, if May can deliver 'a good Brexit' - then the Tories will be in government after each of the next two elections.
From Theresa May's point of view, so far, so good! 
But does this offer clues as to what damage Ukip can do to Labour in their northern heartlands?