Possible Clues:

• Practice of moving time back an hour in spring
• Dawn’s daughter — certainly not heavy
• Starts 15 across with Dawn
• Daughter always fair for broad stretch of time?
• The Count is terrified he'll see it in The Sun presumably
• The hours between dawn and dusk
• & 23 Across Scandalous amount taken in old window tax?
• Diurnal illumination