18a Head of agribusiness seeds it? Not exactly (3-5)
I have: S?T - ?S?DE
I have entered SET-ASIDE which is an anagram of SEEDS IT and capital A but can't parse it.
8d Second -class IT spares-they don't make a dramatic difference (3,5)
I have ?I? - P?R?S
I have entered BIT-PARTS but am not sure...