Poet joins economist somewhere in Buckinghamshire (6,6)
I believe the answer is:
milton keynes
'somewhere in buckinghamshire' is the definition.
'poet joins economist' is the wordplay.
'poet' becomes 'milton' (John Milton).
'joins' is a charade indicator (letters next to each other).
'economist' becomes 'keynes' (Keynes is an example).
'milton'+'keynes'='MILTON KEYNES'
(Other definitions for milton keynes that I've seen before include "town in 21 [BUCKS] - with 16a" , "New city now with Dons" , "Monkeys let in (anag) - English town" , "Open University HQ city" , "Buckinghamshire new town, designated 1967" .)