Understudy gets on, cast in the part of Avebury? (8,5)
I believe the answer is:
standing stone
'the part of avebury?' is the definition.
I don't know anything about this answer so I can't tell whether this works.
'understudy gets on cast' is the wordplay.
'understudy' becomes 'standin' (someone who stands in for someone else).
'cast' is an anagram indicator (letters are dispersed or cast around).
'gets'+'on'='getson'
'getson' with letters rearranged gives 'gstone'.
'standin'+'gstone'='STANDING STONE'
'in' is the link.
Can you help me to learn more?
(Other definitions for standing stone that I've seen before include "Menhir" , "Large rock placed upright" , "Ancient monument" .)