Fire, having caught sight of retreat in range (8)
I believe the answer is:
pyrenees
'range' is the definition.
(mountain range)
'fire having caught sight of retreat' is the wordplay.
'fire' becomes 'pyre' (I have seen 'Funereal fire' mean 'pyre' so perhaps 'fire' could also mean 'pyre').
'having' is a charade indicator (letters next to each other).
'caught sight of' becomes 'seen' (I've seen this in another clue).
'retreat' says the letters should be written in reverse.
'seen' back-to-front is 'nees'.
'pyre'+'nees'='PYRENEES'
'in' is the link.
(Other definitions for pyrenees that I've seen before include "Mountains between France and Spain" , "Mountain chain between France and Spain" , "Mountain range on the French/Spanish border" , "French/Spanish mountains" , "Chain of mountains" .)