I've addressed similar questions a few times in the past. I write here about why the British returned Maine after the war, here about what the British would have done with US territory if they'd won the war, and here I write a bit more in depth about the US war aims. Since the US was the belligerent party and conquest was their aim, to tl;dr your question - there was no real political desire of any consequence for the British to reconquer the colonies. There was little sense that the war had been entirely successful on either side, and neither was interested in pursuing the conflict further at all.