Sunday Times

[bravodeltic]

Need help on some of this one
8d in the end Usain Bolt is fine (6) n?r???
12d essential fact about deer is badly presented (11)
D?S?d?????m
23a attractive cockney giving you clues about 6? (8)
I?v?t???
Thanks again

[Lie-in King]

8d Narrow (fine) - '(Usai)n' (the end) + 'arrow' (bolt)
12d Desideratum ([an] essential) - 'datum' (fact, about) anag 'deer is'
23a Inviting - '(h)inting' (Cockney, giving clues, about) 'VI' (6, Roman)

[scorpiojo]

(Usai)n arrow
D esider (deer is) atum
'In vi ting