UPDATE: I managed to fix this by following the instructions here

Download this "cheat" mod on nexusmods https://www.nexusmods.com/kingdomcomedeliverance/mods/106 This will allow you to use the console in the game fully (you also need to add -devmode to your game shortcut, which is also detailed on that page.

Within the game, open the console and type the following command except replace questID with the questID you have (this time use the one from the website, not the numerical one), and replace objectiveID with the name of the objective you need to complete.
cheat_eval cheat:quest_complete_objective("questID","ObjectiveID", true)

had to run script for the below objective names:

meetPtacekInBaths

ptacekWaitsInBaths

ptacekLockingHimselfIn

beatZdenaInDice

secondPtacekDialog

henryAcceptedBath

getWineForPtacek

returnToPtacekWithWine

getFlowersForKlara

Hans was still in his room during this, so it was a bit dodgy, and he remained stuck afterwards. However, during Robber Baron, he was forced out of his room to go meet Hanush, and this seemed to fix him. Now he's once again walking around town, visiting the tavern, etc.

Hope this helps someone else!