I have 6 Deco x55s. One of the X55 is in a garden room which is about 30m away from the Main Deco and is connected back to a satellite x55 in the utility via an Ethernet connection. This gives me 150Mb connection in the garden room 👍. See picture 

however when the system reboots, the garden room connects back to the living room via a really weak signal (10Mb) and then takes this weak signal back to the utility via the Ethernet cable 

it therefore by default seems to connect the decos completely the wrong way round. 
 

To fix this, I have to switch off the garden room. Wait 5 mins for the utility to connect back via wifi to the kitchen and then when I knock the garden room back on it connects a strong signal via Ethernet. 
 

how can I make the system connect back in this way following a reboot.