I am researching adding an additional subject (German) to my wife's degree. I have read everything here, have been in contact with the teaching council and a university and as a result am even more confused that when I started out

The uni I talked to did not seem to know about the Hdip in the sense of adding a subject and said that the way to acquire the required ECTS points is as a so-called "occasional student". Has anybody experience with this?
The following is also confusing from the Teaching Council website:
"As a registered post-primary teacher, you have met the registration requirement to hold qualifications which enable you to teach at least one post-primary curricular subject. Deployment within schools to teach all subjects is a matter for individual school authorities. It is not a registration requirement to be recognised for additional subjects."
Thanks in advance!