If the laths and the rest of the ceiling are still in good condition, you may be able to get away with having the section replastered. This will require a bespoke quote, as it will need a lath and plaster specialist. If you need to replace the whole ceiling, plasterboard is cheaper, but may not be an option if the building is listed. Depending on the size of the ceiling, it will typically cost a few hundred pounds for materials and labour costs.