On 09/03/2018 20:11, Andrew wrote:
The holes cut for the GU10 ceiling lights are slightly too big and the
edges of the plaster board look rough. Is there a reliable way to fix
this so the finish appears better?

Another option would be to cut out a square panel from the ceiling, fit
a new panel with correct size hole. New panel fitted with a couple of
battens filled and smoothed at joints.