This is annoying to say, but how easy is it to push the skirt back to the wall (it will spring back to being out), but given it's throughout the house were they just tacked on
It's pretty minor throughout a lot of the house. The skirting board I removed was glued as well as nailed on. I suspect it is the plaster fully drying that has done it (and movement in a 100+ year old house).
This is annoying to say, but how easy is it to push the skirt back to the wall (it will spring back to being out), but given it's throughout the house were they just tacked on