Ledger had to include castle fireplace (6)
I believe the answer is:
hearth
'fireplace' is the definition.
(I know that hearth is a type of fireplace)
'ledger had to include castle' is the wordplay.
I cannot quite see how this works, but
'castle' could be 'r' (abbreviation for rook/castle in chess) and 'r' is located in the answer.
'ledger' could be 'heath' (actor Heath Ledger) and 'heath' is found within the leftover letters.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for hearth that I've seen before include "Hot place" , "Part of fireplace symbolising home" , "Area around the fire" , "fireside feature" , "a warm, welcoming place" .)