Why can I no longer connect to Google PlayStore via wifi after software update Samsung Galaxy A3?

[AC Question]

After an automatic software update to Android 6.0.1, I can no longer access the Google Play Store on my home wifi connection. I can access it fine over 3G/4G but NOT on wifi. It comes up with my Google account info sidebar, but won't load the app list to update apps. All other apps, email, internet work fine on wifi, its just the Google Play Store that won't connect.
I've tried:
Making sure the date/time is correct
Toggling from wifi to data and back again
Clearing the cache and app data for Google Play Store and Google Play Services
Deleting my Google account from the phone and signing back into it
Rebooting the phone
Changing my wifi security and turning it off too
Data restriction is not on

I suspected it might be an issue with the network stack not applying the proper DNS settings. To that end, I tried using a static IP address and switching from DHCP to a static IP address reserved for my phone's MAC address, allocating the correct IP address in the advanced settings on the phone's wifi settings.

I haven't tried a factory reset, because it will want to update the phone's sofware automatically which will presumably cause the same issue, as this only started happening after an automatic software update.