I have finished the game and was looking to play new game+ or the dlcs but they are not selectable i have loaded a game came back and nothing is working. I have looked on GOG to see if they are installed and can't find them anywhere but in the folder there are DLC files 1-16. Would be great if anyone could help

I have the GOTY edition btw

To be able to play NG+ you have to save at Kaer Morhen immediately after the game tells you NG+ has been unlocked. You must then use THAT save to enter NG+.

Yes and no, "You must then use THAT save to enter NG+." this is wrong, any save after that save can be used to start NG+, after that save I did the 2 big dlc, with a lot of saves, and any save was good after Kaer Morhen.

What I meant was that any save PRIOR to that save will not do.

So everything i did after Kaer Morhen doesn't count for anything?
One of the dumbest new game+ i have seen.

I have finished the game and none of my recents saves are working new game+ and the DLCs are not playable.

" So everything i did after Kaer Morhen doesn't count for anything?" -it is, but not much.
" I have finished the game and none of my recents saves are working new game+ and the DLCs are not playable." - look like you have another problem, after Kaer Morhen I always do the dlc, never had a problem.

That does not sound right.
You should be able to use any save made after you complete the main story to go into NG+
And the fact that you can't access the DLC definitely makes it seem like stuff is bugged up.
I'd recommend making sure you don't have any mods installed that break the game, or to try verifying/repairing the files.