@RedMeerkat 

Hi,

If your BT SmartHub is connected to your broadband line via a cable connector that looks similar to that of an Ethernet network cable, but is narrower, then you are connecting via DSL and need to buy a DSL-capable router if you want to fully replace the BT SmartHub.

Sounds like you are looking for a router that supports EasyMesh as well. I am not sure if TP-Link currently offers a router that supports DSL and EasyMesh in the UK.
 

  @woozle Thank you. Yes my connection is ADSL.  I might be reading it wrong but I thought the Archer VR 400 (ADSL / VDSL modem router) supported EasyMesh? (though they do call it OneMesh in the description)

You say "fully replace the SmartHub" so I assume that means I could connect a TP-Link router to the Smart Hub and use the Smart Hub as a modem only? Not sure if that's advisable or if it starts to get too complicated!

  @woozle thank you again.  TP-Link don't make it clear that OneMesh isn't compatible with EasyMesh so that's very helpful to know. Looking more closely I realise the WiFi extender I have bought is in fact OneMesh (not EasyMesh - can you tell I didn't realise the difference!) so it will work with the ASDL/VSDL modem router I was considering (the Archer VR400) but is buying a TP-Link OneMesh system now going down an obsolete route?

Yes it does appear that the BT Smart Hub can't be configured as a modem only so my choices there are stick with it (and see if the WiFi extender alone makes the difference to my performance) or get a TP-Link modem/router instead or get an OpenReach modem from EBay and stick with the TP-Link router I have already bought.  I suspect I'm going to return the router I've bought and see what difference adding the TP-Link extender to my Smart Hub makes to start with!

Thank you for your patience with my lack of understanding!