Queen vs bishop + a 7th rank pawn yet dont know how to win it

 engine says more than +6 but how to win ? 

Actually can it be won if black doesn't blunder?

How about:   

Start with Qb7 / Kg2 / Kh3 then bring the King in to support a Queen mate? If necessary, you can allow the Pawn to Queen on the last move before mate.

The idea is to bring the queen to assist in covering the a1-h8 diagonal while allowing the White king to run via either Kh3 or Kf1. We make use of the fact that the bishop is unable to control the light squares to move our king along the light squares.

Just make sure not to interpose the queen with the king by accident.

This is an easy win. Put your queen on a square that it controls the queening square from and advance your king on the light squares, taking advantage of the fact that the bishop only controls the light squares. Obviously if the defending king is right next to the rook pawn then it is probably almost always a draw

I tried playing it doing all the top engine moves, and it ended in a draw by repitition. Maybe this is one of those positions the engine is bad at anylysing?

After 1.Qh7 (as in #4) my Stockfish takes a couple of minutes to find a mate--in 51. Thegreatchessplayer laid out the basic method. The queen controls the queening square, so the king can march up the board to help mate black. Black's king is confined to the back row, which makes mating easier. The bishop has to stay on the diagonal to protect the h-pawn, which reduces it's mobility. It's not a quick process, but it's a sure one

Well, actually Blueemu did it 4 years earlier.

"Thegreatchessplayer" just resurrected the thread and added nothing new.

..

If the defending king is far away then it is basically always a win. If the defending king is right next to the pawn, then it is usually a draw, unless the queen can occupy a square in front of the pawn that is the opposite colored square as the bishop.