We had a room partitioned and want to put coving up on one side of the new wall. What is the best way to cut it in to the existing two sides? - they're butted up square to the new wall, does it have to come down?
If you can get a match for the existing coving, mitre (45 degree) and use a coping saw to follow the edge down, which will then fit up to the existing curve, subject to a bit of caulk. This technique is used for skirting boards, so should work for coving.