Still can't change Google Play country

Method 1 (Requires 2 Phones signed in with same google account):

1. Phone 1:

   
   
   
   
   
   • Open Google Play Store and Download HotSpot Shield or Zenmate. Once
     you have downloaded.
   
   
   • Clear cache and data of Google Play Store by going into Settings ->
     Apps -> Google Play Store.
   
   
   • Now open VPN app (Zenmate) and Change your location to UK and connect
     the VPN. Open Google Play Store and Accepts the terms.
   
   
   • Accept the terms.
   
   
   • Now Move out of Google Play Store.
   
   
   • Do not exit the app from the background.
   
   



2. Phone 2:

   
   
   
   
   
   • Now perform the following steps on Phone 2.
   
   
   • Clear cache and data of Google Play Store on Android Phone.
   
   
   • Open Google Play Store. You don’t need VPN on this phone.
   
   
   • This time, accept the terms and rules. It will take you to UK’s
     Google Play Store.
   
   



3. Phone 1:
   Disconnect from VPN and Head back to Google Play Store.

Method 2: (Same thing on a single phone, but you will need VPN everytime you use Play)

1. Install the VPN app provided by your VPN provider on your Android
   device.


2. Choose a VPN server belonging to UK.


3. Establish a VPN connection.


4. On your Android device, go to Settings -> Apps.


5. Under “Downloaded”, search for the Google Play Store app.


6. Click on it.


7. Press “Clear Data” and “Force Stop.”


8. Exit settings.


9. Relaunch the Google Play Store App.

I have tried Method 2, it worked for me.
For both methods, you need a VPN which provides a UK server(free/paid depending on you).

Set server locations where you want your Google Play location to be, most of the VPN's provide free access to US servers.