@TP-Link Sorry for the long delay in answering I've been ill........ and I've switched ISP's.

The switch is a TP-Link 8 Port Gigabit Ethernet Network Switch (TL-SG108), I's at a point where I couldn't even access the Archer C50 so I had to do a reset.

The ISP and am now using is StarLink, they supply a basic router which plugs into a power deevice which also controls the satellite dish. I have the main Deco plugged into the back of the StarLink router and connected to the other 2 Deco's. One of the 2 Deco's is plugged into a TP-Link TL-SG105 5 port switch and inturn I have a Galaxy 5.8GHz 300Mbps 16dBi Outdoor Wireless Access Point plugged into POE/power device at each end, the 2nd Galaxy is plugged into the Archer C50.

I had the Galaxy Point to Point working flawlessly with my former ISP's gear but the service was too undepenable and unbelivably frustrating that I was forced to switch as my wife could no longer work from home (we live in a very small community with nothing other than high speed DSL which was too slow). My wife is now staying with her Mom in the city where she can work a fibre network)

My view is it has to be the settings between the 2nd Deco and the Archer C50 that is causing the problem but at a point where I'm pulling my hair out by the roots.

@TP-Link Yes, that is essentially the map, the small outbuilding where the Archer C50 is, is just far enough away that the WiFi signal is very week and not stable enough to provide the service we need.