I'm now down to four clues left, assuming I ignore the numerous ones that refer to compilers who I don't believe ever existed... so I would really appreciate help on:
5A Signicant other starting out unsteadily - _ _ _ _ O _ I _
18A Express finally comes to junction out east - no letters!
5D Notes from Taupi as he does needlework outside - _ R O _ _ _ E _ S
6D Complaint made by Imogen and head about pupils - _ _ L _ _ S