Worcester Greenstar CDi and wireless thermostat

Hello Everyone

I have recently purchased and tried to install a Tado system and a wireless extension kit to my worcester bosch Greenstar cdi30

It is controlled originally by a wireless thermostat, the DT20RF

I beleive it is similar to the British Gas one.

Any ideas on how to wire in the Tado ?

I have followed instructions for the DT20 but the wireless transmitter is still controlling the boiler not the extension kit.

I have gone through the 6pin plug. i read a post on here where some were going through the BB ?

Any help gratefully received

Kind Regards