Storyteller climbing Scottish island hill (8)
I believe the answer is:
narrator
'storyteller' is the definition.
(I know that storyteller can be written as narrator)
'climbing scottish island hill' is the wordplay.
'climbing' says the letters should be written in reverse (in a down clue, letters climb up).
'scottish island' becomes 'arran' (island off the coast of Scotland).
'hill' becomes 'tor' (tor is a kind of hill).
'arran' back-to-front is 'narra'.
'narra'+'tor'='NARRATOR'
(Other definitions for narrator that I've seen before include "Someone who tells a story" , "One who tells the tale" , "Teller - or rat ran (anag)" , "Soryteller" , "The one telling the story - arrant or what?" .)