Ft 14678

[Ali-Kat]

11a. Five unusual returns in order describing standard delivery? (7) O?????M
6d. One of twenty-four part-timers (5) T???A
7d. Only friendly mountain to claims, a pick-me-up (8) P???O?I? Think this May have 'tonic' in it, but not sure.
Any help much appreciated as they are my last three.

[elliemay1]

platonic

[emeritus]

7d Platonic

[pixie373]

Platonic

[shaneystar2]

1a overarm

[elliemay1]

overarm?

[Ali-Kat]

Thanks everyone.
That leaves me with 'THETA' for 6d. One of 24 letters in the Greek alphabet and The TA (part-time army).
All finished, so on with the ironing. (Oh, joy)