Never had this problem before, but for some reason, it just refuses to initiate the dialogue, and I have no idea what to do. Previous quicksave before I entered the room doesn't fix it.

If you still have a save from before entering, try putting https://github.com/nwn2fixes/player NWN2fixes in your override folder and then trying again.
See this post https://forum.neverwintervault.org/t/bug-in-temple-of-seasons/4014

Thanks, I'll give it a go.
Small problem, I don't know how to apply any of this or where exactly in the override folder.

Please can you tell me how I apply these to the folder? Not exactly a wizz with code.

On the github link I posted, click on "code", and then Download Zip (see attached download.jpg)
That will give you player-master.zip
Extract that to your C:\Users\UserName\Documents\Neverwinter Nights 2\override folder.
If you don't have an override folder, just create one. (see nwn2_fixes.jpg)
If your on Windows 10 or 11, you can just right click on player-master.zip and then drag and drop the player-master folder to your ...Documents\Neverwinter Nights 2\override folder. With earlier versions of Windows you might need Win-Zip or something to extract the player-master folder.

In the screenshot you can see I already have a 2DA's folder.
If I was going to use the nwn2fixes I would have to remove any conflicting 2DA files.

The first method the OP tried might have worked if he had not put colons on the numbers as Tsongo pointed out.