Inconsistent quote marks - need a way to change globally

[RainbowsC]

I imported a 270 page document from a doc file into Affinity Publisher, then made some changes. Now reviewing it, I note that all the style of quote marks is inconsistent. Some are straight. Others are curly. And most are not curly but slanted. 
I need them to be all the same - regardless of which style. Find and replace isn't working. It won't let me define the different styles of quotes. It won't let me type the key codes in (Option [ or Option ]) to make quotes curly. Using the quote key just produces straight quotes, which are fine if all quotes appeared the same throughout the document. 

I have checked in Preferences and Change Straight Quotes to typographic is checked in Auto-correct. But the program is not changing them. I can delete a quote that is in the angled style and type a straight quote mark and it remains straight. 

It is going to be a nightmare having to manually check every quote mark in a 270 page document and change most. Isn't there some other way, please?

[RainbowsC]

Sorted!  Two problems. The first was that the Find and Replace wasn't working at all. I saw another post in which a user said they had to shut down Affinity Publisher and restart to make the Find and Replace work. I tried that and.... haha!  Quote marks all changed. I was able to use the Option [ combination in the replace field. 
Second problem was that I was using two different fonts to differentiate sections of the book, and I discovered Palatino inserted the slanted quote marks whereas Georgia put nice curly quotes in.
It's all fixed now, thankfully. And it only took minutes, not the countless tedious hours I was dreading!

[Latens]

Thanks for posting the solution( and it's quirks) for other users seeking this answer.