After about 2-3 hours of use, the middle light on the adapters will start flashing green and I lose connection.
How about status of local area connection at that time? Connected but no IP address? Or unidentified network?
The utility will be able to detect the adapter connected to the main router or not?

Hi

what I first see is that I just lose internet, IP address is valid, and router is ok (wireless still works). When I look at the Power adapters both of them are showing the middle light flashing green.
If I check the Powerline utility it only shows the local device, not the remote one.
If I unplug them both and plug them in next to each other straight away, they both still keep flashing green on the middle light.
The only way to reconnect them is to leave them off for about 10 mins and plug them back in. They will then reconnect straight away and everything works fine for about 2-3 hours, then the same process starts all over again.