Help with my set up

Nordicgod

:# Hello all , I have been a tado user for years so I thought I would put it in the mother in laws home , connected bridge V2 and smart thermostat along with extension kit to replace her wireless thermostat and receiver , I followed instructions on app and all I had to do was swap a cable from terminal 3 to 4 on back plate and put extension kit on same back plate , hot water is fine from the combi boiler when a tap is turned on , the app displays the room temp and Alexa reads it fine from smart thermostat , I have set it to lounge group and to connect to extension kit to ask for heat but trouble is when I raise temp on thermostat or via app above what it is reading the heating doesn’t come on and boiler doesn’t fire. the light on extension kit flashes on and off about very 2-3 seconds .I have tried to reset extension kit , bridge and thermostat and paired back up . Also When I press the manual override button the relays click and boiler fires up , so am getting the mother in law to that at moment to get heating . am I missing something??? Hoping for a quick fix from tados end maybe but no response as of yet .
The extension kit and bridge are on latest firmware but the thermostat is still on firmware 24.1 an old firmware I believe , I can’t set it to blink via app or when I change temp via Alexa or app you can’t see it adjust on the thermostat automatically like mine does at home. Do I need to do anything in the installer menu on thermostat? Help appreciated please