Cryptic crossword No 3,776

Across

1. Understanding prompt on headset (7)
2. Improve what one must do to watch Sky (4,2)
3. America starts to upset Russia - protests take place (5)
4. Five finish with chanteuse James causing feud (8)
5. Berserk American sham losing credibility from the outset; (4)
6. The girl abandoned transport boat (7)
7. Queen bee outside given two articles daughter left (10)
8. React as copper boiled lobster, perhaps (9)
9. Court engineers transfixed by bad dance (9)
10. Means to swerve when cycling (4)
11. Most spiteful teams nipping new trainees initially (7)
12. Arizona luxury houses divided into sections (5)
13. Renounce adult book in keeping clear of harm (6)
14. Deprived of seedy adverts (7)
15. Formulaic if forgivable backsliding covering referee? (8)
16. Lake air very exposed in both directions around writer (10)

Down

1. Sculpture and painting almost in convulsions? (4,4)
2. Influence French oddly, enthralled by behind (6)
3. Cold Welsh peninsula hiding source of grouse and quail (5)
4. Investigate obsessive yen leading to endless sex (7)
5. Hesitant sound over 'very naughty boy' from central Italy (7)
6. AC/DC wearing headgear and monastic robes (6)
7. Diddle tabloids regularly, initially missing search for perfection (8)
8. Stew a tortoise heart - no-one wants to touch it (3,6)
9. Polish banker knocked back and German journalist reflected (9)
10. Carry out businessman on pick-up in Perth (7)
11. Saving skin Romeo bolts preceding description of Tybalt (11)
12. Book variety turns (7)
13. Avoided work, leaving second husband annoyed (5)