Something I had not really been aware of till I started to use our fireplace again regularly is the development of the inset stove some models of which are designed to go into a standard sized fireplace opening. eg
It was the sweep who did the clean this Autumn who mentioned them to us and I may well put one in next summer,though I don't think it will be a base model like that but one with a back boiler to avoid dependence on electric which is why we have kept the open fireplace with it's back boiler usable whereas some neighbours ripped theirs out which they now regret though fortunately we have not lost supply this winter so far.
G.Harman