If in referring to National Archives you are referring to UK National Archives at Kew? Online search using their Discovery Search, from main page links to Online Records, narrowed down to "Air Ministry and successors" and results from that to search in both ORBs and Combat Reports with timespan set 1939 to 1946 produces full sets of ORBs and Combat Reports for No.165 Squadron. As example, approx 30 AIR50 Combat Reports covering 1944-1945, and 42 records in ORBs - Summary, Details and Appendices covering from January 1944 to Squadron disbandment in 1945.
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Example screen shot from quick search in UK National Archives online digistised records in just the combat reports: