Consistency of old Tyneside head (7)
I believe the answer is:
oneness
'consistency' is the definition.
(thesaurus)
'old tyneside head' is the wordplay.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'tyneside' becomes 'ne' (region in North East of England).
'head' becomes 'ness' (ness is a headland).
'o'+'ne'+'ness'='ONENESS'
'of' acts as a link.
(Other definitions for oneness that I've seen before include "Unity" , "Singular quality" , "Unified state" , "Agreement" , "#Unique quality" .)