Cryptic crossword No 2,691

Across

1. Trembling tenants start with physical exercise at university (4,5)
2. Serious wound in A and E (5)
3. Help for referee entering difficult university (7)
4. Dem’s connected to the thighs! (8)
5. Wool from feral pacarana (6)
6. Necromancy! Borgias imprisoning enhanced human (6)
7. Retiree, mostly Sumerian and French, freaking out (8)
8. Galloping gourmets no go gathering (6)
9. Revolting rump is art movement (6)
10. Unorthodox, ugly old woman will create academy (7)
11. May to leave mortally wounded giant (5)
12. University at river delta (9)
13. Knock out with spade and suffer, hanging from a yard (8)
14. Chiefly, ring is removed when alimony is arranged (6)
15. Notice to His Eminence concerning bond (6)
16. Pass to Umbria without resistance in river (8)

Down

1. League starts in victory year (3)
2. University computer pal abandons rainbow camouflage (5)
3. Strings he’d rearranged for sleeping in (10)
4. Seats I reposition for nap (6)
5. Old contents of storage device (4)
6. University wife leaves prison (9)
7. Lector not up to making a defensive plan (11)
8. Infuriated Dexter apes a perversion (11)
9. Unsatisfactory U-Boats limp around (10)
10. Vince assuming rule for lethality (9)
11. Stewed oligarch innards for warding off evil (6)
12. Loathing dividing synod I umpired (5)
13. Lock in Royal Engineers (4)
14. Flowers hidden back in Chesterfield (3)