@Solla-topee 

1. My router will not allow me to reserve IP addresses for the devices connected.

2. Power Saving Mode was turned off

3. It is not practical to place the units in the same room.

So for the second questions:

1. Picture below.

2. The link provided was the same as 1. so I do not know how to ping.

3. Yes there is a stable wired connection to the router and then a short Ethernet cable to an AV1000. The AV600 is in a room below.

4. Picture below, there has been no change in speed since the alarm was installed.

Thanks for your help.

@Solla-topee 

The ping details are below.

The detailed topography of my set up is:

The first AV1000 connected by Ethernet to the router, a BT Home Hub 6 provided by my UK internet supplier. This is in my study upstairs.

A second AV1000 downstairs at the rear of the house connected by Ethernet to a satellite TV box. This set up has given me no trouble.

A couple of years ago we had a second Satellite TV box installed downstairs at the front of the house. The installer set this up using a wi-fi mesh between the two TV boxes. This gave us connection problems due to the solid walls in the house. I purchased the AV600 to provide an Ethernet connection to that box. Also the AV600 acts as a wi-fi extender which resolved an issue with poor wi-fi signal to the router in that part of the house. When I bought the AV600 it was supposed to be compatible with the AV1000's previously installed, indeed it gave me good service for a couple of years. Then suddenly it starts freezing.

Thanks for all your help.

@Solla-topee 

Hi

The ping test was carried out with the AV600 working. When it freezes again I will examine if the router has temporarily gone down and if not also try a ping test then. As usual with these problems having had a flurry of failures it has now been stable for six days!

The only device connected to the AV600 is the satellite TV box, it is not simple to try and move this as where it is has been created as a TV viewing room.  However when problems occur I connect my laptop to the AV600 to check the connection. The satellite system itself is flaky, so at times I am able to determine that the AV600 is connected and the box is lying about a connectivity problem. Rebooting the box puts it back on track. However in some instances recently I have found that the AV600 has frozen and that is why I started this post.

I will report back when it happens again with my findings. Thanks for all the help.

Hi

Not much to report after a month of monitoring. I am having to re-boot the TP-Link once a week but the times are random and I cannot determine any pattern to them. This is starting to look like something I may have to live with.

I have given up with the AV600 as the performance was poor. My two AV1000 adaptors work fine between my router and smart TV but adding a third to connect to another room was obviously an adaptor too far. It will be appearing on eBay soon.