You could ask to be winched out of the aircraft to check measurements. For instance buttock-knee may be the limiting factor on the Harrier while functional reach is defined by a particularly hard to reach switch on the Jag etc etc, they don't just invent random limits. If a winch-out proves you fit the real aircraft then you are good to go.
Not sure how easy this will be to arrange as an OASC applicant but it has been done for serving aircrew swapping types for service reasons.
In any event I wouldn't worry too much. 5mm is plenty spare, it's almost half a centimetre
