Water ingress stone cottage

[Joseph1]

My ground floor is about 1ft below the pavement level. It’s a stone cottage that has no dpc. Internally over the years lime plaster has been patched with modern plaster, trapping the moisture. I have hacked off all the modern plaster and will have it lime plastered once I treat the damp. My cottage is a semi and one wall is the back of my neighbours fireplace. This area also has the same problem.
How can I eliminate the problem as I cannot reduce the external ground level? I am trying to do the right thing by the cottage, lime plaster, clay paint. My budget is not huge but I’m looking for a permanent solution.
Any advice would be appreciated.

 

[The Hobo]

does your neighbour have a heat source in his fireplace

 

[Joseph1]

Yes a wood burner I believe.

 

[JML]

As you cannot reduce the ground level and presumably that means also cannot drain or do anything to prevent lateral penetrating damp externally therefore your options a very limited, lime plaster will allow the wall to breath/dry , a dehumidifier will assist in this. Long term l think its just a case of wait and see