The bits that were described sounded like they could have been part of Old Soldiers Never Die, by Roschach's Blot I think? Except that that is firmly in Harry's timeframe, what would be fifth or sixth year if not for doing a mic drop in the first chapter. The part where the mundane intelligence service are quite aware of the magical world and have various assets tasked with trying (with more or less success, but far more than the MoM is aware of or would be happy about) to keep an eye on the "funny hats," at least. I haven't started on the one linked above yet, but if that impression holds true it may be what you're thinking of, or similar "doing things the muggle way" stories.
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‎noli esse culus
‎noli esse culus