Thanks for the recommendations. Its for residential use, but at the same time I want to buy best kit within reason. Wifi will mainly be used on the ground floor where the modem/router will be. On the second level its more for convenience and on the third level it will hardly be ever used but will be nice to have it going that far.
I'm not going to be able to get a cable through the house because without causing a mess. Cabling makes sense though, and will consider routing it from the outside. But if I go down that route I will need to find some extreme cabling which will cope with extreme winters (-50*c)
If I did get a new router. Say like two TP link routers with multiple modes (router/range extender). Will the range extender require a LAN cable to get the internet to it or will it pick up signals from the router wirelessly?