White and blue smoke in the exhaust pipe when the car is cold

Hello

I own a 2012 auris diesel. For about 2 months, it has been emitting white and light blue smoke from the exhaust when the car is still cold. After I went to the local Toyota garage I was suggested to change the glow plugs as two of the four were dead, I also changed the accessory SCV 0928400606. The injectors and other components are OK

The smoke did not stop coming out and so I thought of cleaning the lambda detector as well. Do you have an opinion? Will cleaning the lambda detector help to stop smoke coming out of the exhaust pipe? Do I have to do anything else? I am desperately waiting for answers

Thanks