Live View Not Working and poor RSSI

Just installed Doorbell 3 Plus. Initially RSSI was mid 60's and live view was very hit and miss 'Activating Device' most of the time. I therefore got a WiFi extender which changed RSSI to 48. Today RSSI back to - 62 and Live View gone back to activating device. WiFi extender is only 1.5m from doorbell. Only UPVC door and part of wall between Bell and extender! Battery level of bell is now in the high 80's. Bell seems to work OK when someone approaching or ringing the bell. Moved bell into house by wifi extender, RSSI reduced to -31 but live view still activating device. I have followed all your advice so what else can I do?