Cryptic crossword No 3,988

Across

1. Cleared out area by pigpen strong in smell (5)
2. Where to eat meal in restaurant... or this meal picked up? (9)
3. Get up in old tan clothes (5)
4. Charming one with Spooner's sixpence (4)
5. By a great deal, perhaps, ewe and ram present in hindsight! (4,7)
6. May I start to rebuild cracked burial monument? (5)
7. Taps built without one good absorbing apparatus originally powered with energy (7,2)
8. Canine led organized trip in rows (4-5)
9. Placing after the sixth-place winner out of bounds in contest (5)
10. Fashionable ref essentially umpired professionally without fail (10)
11. What's done to Lear's crown in play? (9)
12. International assembly has pictures capturing a get-together with left out member of parliament (11)
13. Stiff kitchen utensil cutting skin (3)
14. Question papers for unit in London? (4)
15. Finishes equal intense aid in transport (4,2,1,3)
16. Half brash? The opposite! (3)

Down

1. Arrest one charged assuming utter makeover (11)
2. Half-heartedly gazing at one piece of litter of a bag possibly (3-2)
3. Annual assembly's ending prematurely (6)
4. Spooner's factory prohibition caused one to fight with Pole (7)
5. Meets kind understudy covering up blisters (7)
6. Regularly cuts upper lip on pipe in movement going against head (8)
7. Backpacks? Better have this backing! (7,4)
8. Old chemist's final cure half used, see extra (9)
9. Puzzled queen with starts of college assessments lecturer takes; 1 + (0 x 2) + 1 (9)
10. Class flying off in damn airspace (3)
11. Treated with disrespect, follower stopped supporting lead journalist (8)
12. Earl set up walls known by deliberate divulgence (7)
13. Ring unionist in dense forest succumbing to onset of insects (6)
14. Returning on second thoughts, I enter initally asking tavern for drink (3,2)
15. Cross the river Styx to wash reportedly (3)
16. Perhaps Burundian Franc is in circulation with American imports primarily (7)