@Batchy8 

Hey

To be perfectly honest, in terms of black spots the only real way to get rid of them is more access points.   While swopping to an AC1200 might help a bit (due to its larger antenna) its unlikely to be the solution you are after.

Personally I would recommend you look at installing a Deco Mesh, this would be a better coverage solution for you.    As you are using a 4G router and not fibre to the house, your internet speed isn't likely to be more then say 200mbps?    If so something like the 2x M4R Deco would offer you similar speeds to what you are getting and additional coverage for a fairly cheap price.  If you want faster WiFi for some reason look at the 2x  Deco x20 models as they are WiFi6 so faster, but likely overkill for a 4G connection.

In a Deco setup you would have two nodes, one will sit near your EE router to replace its WiFi, the other dotted somewhere in the middle towards your black spot to repeat / cover that area.  Basically the two nodes talk to eachother and the second one being closer to your black spot should cover it for you. 

You are best turning off the WiFi on your EE router and using the Deco only, reason for this is a thing called ROAMING.    Deco supports roaming, therefore if you walk from the Main Deco to the Black Spot Deco it will hand over the connection between the two nodes without disconnecting you, if you are on the phone / watching a video etc it will stay connected.   Your EE router wont support roaming so will kick you off when it loses signal, therefore use it only for internet connection, let Deco do the WiFi.

To set this up its pretty easy

1.  Turn off EE WiFi, this will now only provide you internet connection (no WiFi)

2. Plug first deco (Main Node) into the EE router in one of the LAN ports and power on. 

3. Use App to Setup the Deco..  Internet choose AUTO (should be fine)

4. Place the second Deco mid way / two thirds of the way to your black spot and power on, this only needs a power cable (no LAN).  Setup in app

5.  Enjoy your new WiFi!