I have 4.04 installed and it runs fine but in gog galaxy, it keeps on trying to update it and download 45gb worth of stuff even though the new redkit should only be 3gb ish.
This is happening under the original wild hunt and not the complete version.
Any ideas on fixing this?

Manually download from the game downloads in GOG.com > Your account > Games (or from Extras on the game page in Galaxy), the following files:

Patch (4.04a to 4.04a_Launcher) 4.04a_Launcher (1 MB)
Patch (4.04a to 4.04a_Launcher) 4.04a_Launcher (623 MB)

Then close Galaxy if it's open and install them. Once installed open Galaxy and it will automatically update the game to its latest version.

*In my experience, the latest updates cannot be installed, do not download them, Galaxy will do it for you, they are these:
Patch (4.04a_Launcher to 4.04a_REDkit) 4.04a_REDkit (1 MB)
Patch (4.04a_Launcher to 4.04a_REDkit) 4.04a_REDkit (3 GB)
It's that and on general it seems to be some discrepancies with the latest updates and the most recent offline installer files, or something like that.

I hope that helps.