Writesbad I don’t think that can be right. Letters are S?E?E unless I have the answer to 2d wrong which is “Dim former pupil undoubtedly catching cold”. Answer “obscure” Old Boy OB with Sure (undoubtedly) containing a C (cold).
“Say” is correct. Day was wrong, sorry. Therefore Shoota has cracked it. But definitions do not state “siege” as collective noun for herons, just bitterns! Benefit of doubt to setter.