Operation Grapple 1957

[ChristchurchPS]

I have attached a scan of a cover that I am researching, but wonder why the item went to Hong Hong.

The item was postmarked at Christmas Island to NZ on 24 AP 57 and  backstamped FPO 701, 29 AP 57 - [?? BFPO1 Whitfield Barracks, Hong Kong].
The back flap is missing so there are no details of the sender.
Most of the mail to NZ addresses is from Navy personnel serving on HMNZS Pukaki and HMNZS Rotoiti, at this time neither ship was at Christmas Island but on 16 April 'Rotoiti' had undertaken a mail transfer with HMS Warrior near Malden island, and later that day handed over mail to 'Pukaki' from this mail transfer.
On 21 April [Easter Monday] 'Rotoiti sailed from Area Alpha towards Malden Island to meet with 'Warrior' for another mail transfer

[b]Does anyone have items from Op Grapple:
  a:  backstamped Hong Kong, to other destinations?,
  b:  to this recipient?.[/b]

Thanks
Robert Duns