Currently we have a Vodafone UltraHub with Fibre 100 and one wifi extender but it doesn't cover the whole house. Im wanting to upgrade the wifi and thinking a mesh system is the way to go. Almost everything is connected to the network via wifi and not cables so good wifi is the key.

My question is if I buy something like Tp-link Deco system (https://www.tp-link.com/en/home-networking/deco/deco-x60/) which comes as a three pack of units does the first unit plug directly into the Ultrahub (via cable) and stay near it and the other two units can be placed around the home or do all three units spread around the house (and connect via wifi) once they have been set up.  

Also I guess is a mesh system like this compatible with the VF Ultrahub in the first place? 

If anyone has any advice or experience setting up a mesh system, it doesnt need to a tp system - that worked! - that would be great!