I one of books with biographies of Polish airmen flying in UK and KIA/MIA during WWII I have come across an interesting information that details of their losses may be found in certain Air Ministry Orders, for example: Order no. P-355430/40 - regarding Sgt Egierski killed on 13/14.10.1940 or Order no. P-376334/42 - regarding Sgt Furmaniak shot down on 5/6.12.1942.
Does anyone know if such Orders (or perhaps rather Reports?) may be found in National Archives at Kew and what reference they may have?
Any assistance would be appreciated.

Regards,
Greg