If you are/were on AFPS75 then the 30 day rule no longer applies; I know this as I did exactly this last year and got my pension and gratuity within 10 days and started my FTRS post within 2 days.
Speak to Lt Cdr (rtd) David Marsh of the Forces Pension Society and/or SPVA for full confirmation - that's what I did as 'belt and braces'.
All the best
LJ