Though I could not show a valid Certificate of Good Conduct immediately, I have sent attached all of the available documents to the company.
I have also written that since they asked for this certificate a bit late - taking the time limits into consideration - it might happen that I will receive it on the week commencing with Februray 20 only.
They replied immediately and thanked me very much (!) that I posted in my documents and they have already started the background process with their service provider company. I have recived a form to fill from them which I filled immediately so my case is on its course.
Today morning me and my wife received a notification from the government office that the certificate has been posted. Hooray!