I work at Norwich Airport and to be honest we know when military aircraft are about because of their noises.
In the last few weeks a coupl;e of F35s have done low-ish Runway passes and we don’t expect them to land. Therir noise is quite loud compared to all others,
Other regular Mil passes are A400Ms and 146s.
The F15s dont bother NWI at all due to their height but we may watch them on cloudless days.