Cryptic crossword No 2,981

Across

1. Turkey Post Office go after university left? (7)
2. Type of chemical all around company house (7)
3. Plant set in patio, bizarrely (10)
4. Small drug seen in photos adds flavour (6)
5. "NASA's a cult!" - Irregular for man who orbits entire earth in one night (5,5)
6. At sea, car refusing coming back out of the water (11)
7. India after English joke - grand for entertaining! (8)
8. Leader of discussion is after member's seat (8)
9. Swan back with energy for a scoop (4)
10. Cheese is core component of sobriety (4)
11. Rhode Island has books regarding streamer (6)
12. Gym brilliant after a time, now resting (2,5)
13. A dozy one found on the railway? (7)

Down

1. Anarchic Carl, he sang for heaven-sent leaders (10)
2. Some caribou ill onto soup (8)
3. Longing to return after day in Calais for march (7)
4. Tradition for Turkey: seduce Arab around! (5,5)
5. Drinks a large, starts to effuse and sway (4)
6. Optimistic, throw pie afoul, discarding every other piece left (7)
7. "Rang her - daft, silly" - mum's dad? (11)
8. Drinks from very smallest bar: getting out, a number inside (7)
9. Abominable yeti after significant other, one hundred in community (7)
10. English head went first, honoured (8)
11. Attacks pests aboard ship (6)
12. Larger horse got into German alcohol (6)
13. Steal cut (4)