Replace window first or remove window sill tiles?

You can remove all the old tiles and get the window replaced afterwards. the window fitter should also fit the new sill unless you want to tile it.

I would remove tiles then replace window, it is necessary to remove tiles first but it gets them out the way. Once window is replaced then re tile as you will tile upto the window.

When I have done kitchens I get the window changed first. Or at the time I start the kitchen install. Some window fitters can be a bit boisterous and I have seen some damage newly fitted worktops. They fit the window sill that the window sits on but they won't fit the sill on the inside for example MDF window board/tiles. After the window install the reveals can then be made good prior to tiling or painting. Hope this helps.

You can move all the old tiles first because normally when you take the old tiles of the wall it depends how well they have been put on with the tile adhesive you always find that the plaster comes off with the tiles . then take the window out because when you take the window out you allways damage the plaster around the window so that will need bond out around window so you can all so bond the walls where you have taken the tiles off if need then plaster the walls and plaster around the window reveals and the window fitter will fit the cill when he put the window on Thanks jcw builders

I'd remove tiles so as not to damage window also this will not hinder the sealing of window and help tiler to butt tiles upto frame also be good idea to leave covering tape/film on inside of windows to restrict damage to frame whilst tiling etc being done