Related Clues:

• An SOS form whatshisname?
• You've forgotten the name of 20 down, perhaps
• Sounds as if 27 across comes at the double for whatshisname
• Seems you don't care for the one that's forever needling, by the sound of it
• SO2? Can't recall what you call it
• Thus more than once the name of that unpleasant person escapes one
• For this unpleasant one, see 27 across
• SO2 for whatsisname
• SOS?
• Forgotten his name, but thus he is doubly unpleasant (2-3-2)
• One does not care for two such
• Whatshisname is a dreadful fellow
• Thus twice as unpleasant as this
• Perhaps SOS for such a such-and-such
• Not like one like this