The original Rampant mod is licensed under the GNU GPLv3 license which makes it pretty clear that you can distribute modified copies of a piece of software provided you:

1. state any changes you made.
2. license your version under the same license.
3. include a copy of the GNU GPLv3 license and copyright notice with your version.
4. disclose the source code of your version.

This mod does not meet conditions 2, 3, or 4 which is a problem and technically grounds for the original mod author to request this version to be taken down. The fix is pretty simple; change the license and publish the source code somewhere (e.g. GitHub).

I love this mod and would like to see it stay up hence why I'm raising this issue.

Point 4 is not an issue (from what I can see): source code (Lua) is included in the mod download. Putting the contents on a collaboration platform like GitHub would be a nice extra but not required.

I agree on the other points. In particular, the "non commercial" part of this mod's licence is not compatible with GPLv3.

I tried. Veden demanded that I return the license for the one that is in my mod now. I don't know if he had the right to do so, but I chose not to argue.

https://mods.factorio.com/mod/RampantFixed/discussion/6254d1a7e3e23bc4fcc944ba

This was during the time of versions 1.1.9 and 1.1.10 (Rampant Fixed).
You can look in the changelog if you are interested, or download version 1.1.9 for license GNU GPLv3

By the way. If you raised the licensing issue to find out if there is a restriction on streaming, then I only welcome it. And just in case, this is indicated in the FAQ
https://mods.factorio.com/mod/RampantFixed/faq

I tried. Veden demanded that I return the license for the one that is in my mod now. I don't know if he had the right to do so, but I chose not to argue.

https://mods.factorio.com/mod/RampantFixed/discussion/6254d1a7e3e23bc4fcc944ba

Thank you for that context, very helpful actually! I assumed that because Rampant is currently GNU GPLv3 that your version was forked from that version. This clearly is not the case based on the discussion you linked.

Consider my concerns on the licensing issue resolved.