Think differently

I see the mate that is available, but then I'm distracted by the Queen threat to the Bishop and pawn.

As I cannot make the mate work, I switch to the distraction and decide that it must be the main point at issue.

I am wrong, of course. 

Although I am correct that the mate that I tried doesn't work, it is still available, just not in the obvious combination I envisaged.

Lesson available ( and learned, I hope). Think differently.

White to play

Solution if required