The answers are all surnames of famous people called Tom, Dick or Harry.
1. On the whole, it's a holiday
2. Prickly flower head is a hundred (thistle-ton??)
3. Vowel gets a vacuum cleaner
4. Follows air, space and tight on the isle of ...
5. Cavity sounds like a narrow thoroughfare (hole? Lane?)
6. Make impertinent enquiry alternatively
7. Bird talk for each (chirp? Per?)
8. Radio operator gets 2/3rds of a day
9. Alone, the saintly animal lover
10. Letter did allow famous female singer (?let?)
11. Headwear is a heavyweight (cap?ton?)
12.the late miss Emberg found in a church with a vowel (bella??)
13. Sounds like a letter gets a meadow (?lea)
14. Mixed up turnip
15. Heavenly body with lock opener (Angel?key?)