Splendid party admitting some number after daughter’s left (7)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

Splendid party admitting some number after daughter’s left N (=some number) in SHIN <d> IG (=party, knees-up; “after daughter (=D)”s left” means letter “d” is dropped); cf. a shining example of