One in the outskirts of Henley is dear (5)
I believe the answer is:
honey
'is dear' is the definition.
(I've seen this in another clue)
'one in the outskirts of henley' is the wordplay.
'in the' indicates putting letters inside.
'outskirts of' suggests removing the centre.
'henley' with its centre taken out is 'hy'.
'one' going inside 'hy' is 'HONEY'.
(Other definitions for honey that I've seen before include "sweet thing" , "Nectar product" , "sweetheart" , "Sweet yellow liquid" , "Treasure" .)