. The roof was leaking but has been fixed and this was the source of the damp and the reason for re-plastering in the first place.
If the brickwork was actually wet, due to a leak, it can take many months to dry out. Some bricks may be harder or less absorbent than others (especially in an old terraced house where the builders may have used cheap bricks), and often you can see the pattern of bricks showing through the plaster in damp patches. Are the damp patches showing as a chocolate colour, and the dry plaster pale pink?
Usually the way to dry out is by opening the windows and giving it plenty of ventilation, but in this weather I expect you are reluctant, and anyway, it is so cold that there will not be much drying, you might even get condensation if the wall is very cold. If the window has a trickle vent, leave it open. Once the frost has gone, ventilate it more. When you redecorate this room, use a Matt Emulsion (non-vinyl) for at least a year as this lets it dry out best. Dulux Trade Supermatt is good.
When you say an old terraced house with lime plaster, I picture something from about 1900. In this case it will not be a cavity wall. Measure the thickness of the wall at a door or window opening, if it is nine inches plus plaster, it is solid. People who like old buildings usually say that if they were built with soft bricks and lime mortar, you should not use cement as it is too hard and not so porous. I don't know much about that.
Some photos of the wall (inside and out) will help.