@TP-Link 

Hi, yes all units wirelessly linked with each other through the app. 

When I checked the units, all 'lost' units on the App were showing red when I checked. 

When I reset them all by turning off the whole house, it always brings them all back. And when checking they all seem to have a good signal between units. Some with PLC. 

The main Deco P9 is the only unit that does not seem to lose connection. 

Hope that helps. 

@TP-Link 

Hi, it was a mix of both. Sometimes the units would show red LEDs and the App would show them as okay. Other times App would show them offline, but a white Led indicating okay. 

Today I have done a complete reinstall of all the units and changed the network cable between the main Deco and the Plusnet router. 

So far after 8 hours of running in AP mode I haven't had a single dropout. I shall update if I manage to go more than 24 hours. 

Cheers. 

@TP-Link 

Woke up today and 5 out of the 9 units have disconnected. Despite all having strong signals and were fine for 18 hours. 

Confirmed on the units they have red LEDs 

@TP-Link 

Thanks for that.

The units have been slightly better than before after creating a new setup.

Have tried a few times to do the firmware update but struggling with Javascript void errors on multiple browsers. Will continue to try and report back.

Okay after pulling my hair out with this for the last 4 days I have found a workaround.

I'm not tech savvy but I believe its something to do with the DHCP and how if the modem router DHCP drops out the TP-Link Smart DHCP kicks in on the deco's. However when the main router comes back online it doesn't revert back to previous situation.

I started a new network and after installing the 1st main unit, put it into ACCESS POINT mode. Then proceeded to install all the other units (8 of them) without issue. This worked perfectly for EXACTLY 24 hours, then dropped out.

I noticed my LAN lease time on my Zyxel router was set at 24 hours. Changed this to 365 days.

With every deco unit switched off I then switched each unit back on, one at a time starting with the main unit. Give each unit a few minutes to connect and move to the next. Eventually got all of them back online and after 36 hours everything seems to be working without issue.

I haven't tried going back to ROUTER MODE as I'm just happy to have the damn things working, albeit without some of the features.

I stress tested the system running HD video on 6 TV's and 3 mobiles running Youtube, no problem at all for them.

The ONLY issue I see now is that should there be a power cut I will need to switch off all the decos, once the power comes back on reintroduce them. Not an issue for myself as we have a stable supply, but could be a problem for others elsewhere in the world. 

I hope this helps others, and if you see this before buying them then consider purchasing very carefully, as they seem fundamentally flawed and shouldnt be this difficult to setup

@Ayrhead 

Okay this is my final post on this subject. 

Bottom line is, these units are not fit for purpose.

 I tried every configuration/workaround to get them working and I was still getting random dropouts. Rebooting would solve it sometimes, other times not. The Web based app is also incredibly unresponsive and does not reflect what you are seeing on your network in real time. 

I gave up, nearly. £500 in mesh units that simply do not work reliably. 

I have now spent another £450 on Tenda MW12 units which after a week of installation have not given me a single issue.

Please stay clear of the deco P9s.