The Geoid models can be downloaded on our official 3Dsurvey website under downloadables. After clicking the link you first need to log in with your 3Dsurvey account, and under Geoid you choose the one you need. If the one you desire isn’t there, just write a reply in the Forum or write us an email on support@3dsurvey.si
Here is the link to the downloadable Geoids:
https://www.3dsurvey.si/account/downloadables