Good family will take her to find London landmark (7)
I believe the answer is:
gherkin
'find london landmark' is the definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.
'good family will take her' is the wordplay.
'good' becomes 'g' (abbreviation).
'family' becomes 'kin' ('kin' can be a synonym of 'family').
'will take' is an insertion indicator.
'g'+'kin'='gkin'
'gkin' enclosing 'her' is 'GHERKIN'.
'to' is the link.
Can you help me to learn more?
(Other definitions for gherkin that I've seen before include "Small cucumber, usually pickled" , "Vegetable of the cucumber family" , "Immature fruit of cucumber" , "Cucumber for pickling" , "Cucumber - London skyscraper" .)