BT 11ac WiFi Range Extender - AC 1200: Not passing internet

[Davred61]

We've recently moved into a three story Georgian townhouse - thick walls!! The BT router is sited on the first floor and gives good coverage on that floor and not bad on the top floor.

Downstairs there's an AC1200 Extender which is sited well and is getting a good signal from the main router.  Most equipment attached to this extender is getting 'good' or 'excellent' signals. 

In addition, there's a BT network-over-the-mains pair with the remote unit in my office.

My issues are three-fold!

1. At least two or three times per hour, anything attached to the AC1200 will stop seeing the Internet. On our TV, this means Netflix or Amazon Prime, freeze and try reloading. On checking the TV's system settings, it shows a connection to the extender but 'no Internet connection'. Same thing happens on my PC...shows as connected to the extender but no internet access. As I frequently have to run software tests on this machine, losing connectivity is not at all good! The router is showing as having an 80mbs connection throughout.
2. I've tried using the mains LAN unit...this behaves fine (mostly green data light) when the switch connected to it has just a printer and NAS plugged in but when I also connect the PC  we get yellow and red data lights and hopeless throughput of 6mbs.
3. Wireless speeds are not too clever..on the AC1200 Down is 5mbs and up is 7mbs despite showing good or excellent!

I don't expect the full 80mbs by wifi, but it's proving very hard to work at the moment!

Are the range extender 'discs' the only answer (apart from running a LAN through the house!!!).

Thanks

David

[licquorice]

If you need 100% reliable connectivity, the only way to go is Ethernet. Wifi extenders are a very poor option in my view, their location by definition is always going to be a compromise and they halve the speed of any wifi signal as they are transmitting and receiving on the same channel. Powerline adators are usually more succesful but are reliant on good mains wiring.

[Davred61]

Thanks @licquorice. Well being a bit old-school myself I'd agree with your opinion on extenders - it's a shame no-one has produced a Duplex design.

Our wiring is newish - last 4 years and so I'm a little surprised that the data transmission is so poor. I've tried the units on the same ring and differents rings but the red light on data remains!

Thanks again.

[licquorice]

Hmm, does seem rather odd, I have a set of 3 mini hotspot 500s here that work fine on 40 year old wiring.