The blockhead gets these sorted, by order! (6)
I believe the answer is:
behest
'order' is the definition.
(I've seen this before)
'the blockhead gets these sorted' is the wordplay.
'the blockhead' becomes 'b' (head letter of 'block').
'gets' says to put letters next to each other.
'sorted' indicates anagramming the letters.
'these' with letters rearranged gives 'ehest'.
'b'+'ehest'='BEHEST'
'by' is the link.
(Other definitions for behest that I've seen before include "Order" , "Command, bidding" , "Command - Thebes (anag)" , "(At someone's) command" .)