The discrete search is not in Power, it is part of the Experience add-on. You mentioned the retired Enhanced Search, the functionality for all the Enhanced add-ons is now contained in Experience add-on. I shared the link to the documentation for discrete search.
The Experience add-on also allows for a Dropdown menu for countries. You can also add labels in the address box to request people put in more information so that Google will come back correctly. What I meant by a blinder, is: Australia does not have unique postal codes. Google will return other countries that could have a similar postal code. I have attached a screenshot, using GOOGLE MAPS (not SLP) and requesting zip code 2100 there are 3 results returned. Belgium, Portugal and Denmark…which one am I looking for? It didn’t come back with Sydney. Thus the experience add-on and the Premier add-ons have added things such as autoocmplete address which will pre fill with locations from your SLP locations list. I hope this clarifies what I mean by having blinders on. Obviously Google comes back with the most common searches when someone types in a postal code of 2100. See How Search and how Google MAP API works
To be able to assist you properly , please read the posting guidelines. The screenshot we need is of your Plugin environment (see Posting guidelines)
As a side note: The developer is looking into changes that WP made as security patches in how SQL was being handled. WordPress 4.8.2 updated how they “fixed” string security. They also then changed another set of rules in 4.8.3 but it wasn’t in their codex. The developer is working through their CODE now to see if it could have any impact on how search javascript is working in the event that Google has not changed their algorithms.