Inoue Dōsetsu Inseki is very forgiving with amateur's mistakes. There is a simple way to avoid Harry's trade: Play the forcing moves in the hanezeki earlier.
We now think that it is best to insert the forcing moves Black and in the hanezeki immediately after the guzumi exchange ( - ) in the top right corner.
This guzumi exchange just destroyed Black's option for choosing Joachim's Ko-Semeai (i.e. not completing the Crosscut Sequence - , but playing the hiki of Black instead of connecting at ), because the potential ko shape ( / ) in the guzumi area is no longer available.
At this moment, White does not have any chance to counter-attack. The hanezeki's tail cannot be captured, as it is not in atari, and the left side is still untouched, with sufficient options for Black.