Cryptic crossword No 1,244

Across

1. Sort of seed that might follow Open for a spell (6)
2. See 27
3. Off bingo, we're all doing strip poker (6)
4. Sensational Republican fiddle covered up by Washington (8)
5. Old royal fighting legendary boxer? Then there'll be fireworks! (6)
6. Fan urging Queen to be more like Nirvana? (8)
7. Better witness finally recalling reg number right (8)
8. Little raver dances round Methuselah, a person of some advanced age (4,9)
9. Biblical son getting some stick, we hear (4)
10. Long year on International Space Station essentially very hard (8)
11. Spare piano brought in for Part 3 of Get Back (8)
12. Original new musical heading to West End (6)
13. Veterans make relationship public, but not at first (3,5)
14. Do without - resisting id, then? (6)
15. Soldier heartlessly sent back makes news (6)
16. Old President Trump gets books by English author (12)

Down

1. Speculative work discussed a couple of hypothetical variants... (3-2)
2. ...another is turning up with gamma, oddly (5)
3. Symbols in gospel linked with one or two older books (8)
4. One's used to Count Dracula ripping layers off and biting through bits of muscle (6)
5. Old aunt and gran upset a relative of ours (9)
6. Perhaps skinny superhero's clothing falls off in the middle of deli (9)
7. Might they find fault with your setter, potentially giving grid one star? (3,8)
8. See 15a
9. Given this, heir's now drunk on power (9)
10. Mean or represent or merely mean to represent (5,3)
11. It's Austen on one side, latterly, or the Queen if you turn it over (6)
12. Some uncouth rumours creating buzz (5)
13. Fussy eater kicked off when given the wrong starter (5)