it is very very rarely rising damp, it is highly likely to be an inappropriate material used on the walls and that can be fixed (if you are competent in DIY it will probably be much cheaper to do it DIY. If you are buying an old house with ‘problems’ it is best to learn about the problems and how to fix them. Find a great FB group like ‘Your old house - repair and conservation’, it is full of people posing questions and experts and people who have fixed problems themselves giving examples of what they have done. I would say it is about 1/3 damp related.
If you like the house and think it is perfect in every other way and the price is good then you wouldn’t want to pass it up because of a completely fixable problem.
I hope you get it because it seems like a lovely little house!