@Chuckoir 

As mentioned in my earlier post I have managed to get mine working over power line and seems to be stable after a few days (ideally I would like to optimise positioning but dare not unplug in case I lose it).

I have v1.0.  
Firmware: 1.0.3 Build 20230420 Ref 77020
 

Yes apologies - I will try the same later this evening.

@Andrew155 how did you reset it, just by pressing the button on the back?

  @Andrew155 Thank you! Success

So I thought I would give it one last go before I end up having to return them.

Here's how I got mine to connect using powerline following @Andrew155 advice

Using latest firmware.

1. Deleted my entire network in the app.

2. Swapped the decos around and started with a different one as the main unit.

3. Setup main unit from scratch after using reset pin in the back and set the network up again.

4. Plugged in first satellite and again used the rest pin.

5. Confirmed that showed the powerline symbol.

6. Repeated with the other satellite.

Not completely sure which of the above steps helped but its all working atm.

Hopefully it will stay that way.

  @Frosticles 

Is the main unit still plugged into your modem, or does it not need to be that way?

If you've reset them, are they not on the base firmware (or have you updated them again)?

  @Chuckoir 

Yes my main unit is plugged directly into my modem. I am using these as my router and not just an access point. My original BT router is packed away. I have set them up as you do on first setup I have just used a different deco unit as the main one, and the one that was my main unit is now a satellite unit.

The firmware seemed to persist after using the reset pin (assuming I did it correctly as its really hard to tell) and is still on the latest version.

I removed both satellite decos in the app menu before removing the main one and starting all over again.

  @Frosticles 

Followed the instructions and can confirm that's fixed it. 
 Reset two units while they were connected to a double socket. 
 Promoted a px50 to the main unit.

moved the other unit to the main bedroom

removed the x75 pros from the network

PLC and WiFi now showing as the routes between the units

Now wondering how to send back the X75 pros. 

@Frosticles @Andrew155 - Thank you so much!!

Thank you both for the clear instructions. I used the node from the office and set that up as the new hallway before adding the satellites - one-by-one each one miraculously connected to PLC+WiFi!! I have rebooted into Access Point mode and the PLC has remained intact.

I wonder if it is because everything (i.e. both app and deco firmware) are already the latest version before setting it up again fresh? I do also wonder whether it REALLY is connected via PLC at all or if this is just an icon change... any thoughts on how to test this?

  @Dracon I might organise another support session for the engineers to remote in and gather up log files. That would show if it's working or not. Oh and checking to log file to see if the PLC status is no longer set to 3 but something else. 

  @ommoti @Dracon 
I had a look at the log files using the web interface and by resetting the units fully it seems to have cleared the critical errors that were showing in the log file when working with support previously. 
 I have done a search through the logs for PLC but nothing comes back, that's not to say its not working but I think its now booting up correctly compared to the previous attempts.
Wondering if the PX50's being sent out from Amazon have a bit of an config issue left over from the firmware being installed during manufacture, the reset then clears any information that shouldn't be there. Do the PX50's use encryption over PLC? Maybe an encryption key that's malformed/corrupted that then clears by resetting the units?

Either way thanks to those who put the instructions up as I know have good coverage throughout the house.

I too have now solved the issue using the steps posted by others above - thank you everyone!

Here's a shot before I rebooted and moved the units around (both satellites in the kitchen)

Removed from the network, rebooted and set up as new network - reconnected both units in the kitchen again, then moved the office one to my actual office at the end of my garden, and voila:

Hopefully we don't have to go through this ballache every time there's a firmware update??!