This glitch has hit me in the past involving the gangs of Novigrad quest but I just came across it while doing the swords and dumplings quest, whether or not this was the trigger I'm not sure. Upon completing the quest I went to fast travel but nothing happened when I clicked on signpost from the map screen. I tried varifying the install but that didn't find anything wrong, I loaded up earlier saves but that didn't help, I tried disabling mods and installing the fast travel mod but still nothing. Anyone got a fix for this or is my game screwed, I'm halfway through NG+ and was looking forward to getting to the DLC for the first time but I don't know if I can be bothered to start again.

It is not enough to disable mods, you have to remove them completely while troubleshooting. Moreover, you need to pay attention to versions and instructions. For example, if you have the mod that shows all quest locations, the info page specifically states:

"Don't install the compatible file from Colored Map Markers with the lite version! Use the main file, otherwise you won't be able to fast travel."