Well-established place for horse (6)
I believe the answer is:
stable
'place for horse' is the definition.
'stable' can be an answer for 'place' (I have seen 'Place of birth' mean 'stable' so perhaps 'place' could also mean 'stable'). I'm not certain of the 'for horse' bit.
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for stable that I've seen before include "Horse establishment" , "Products all from same place" , "Steady - home for dobbin" , "Bleats (anag)" , "Steady place for a horse?" .)