The simple cockpit mounted 'G' meters in most British military aircraft are designed to indicate relatively steady state forces. In the event of an impact, cockpit readings will not be an accurate reflection of aircraft structural loads. Strain gauges and/or Fatigue Meters installed near the aircraft CoG are designed to record these forces (strain gauges measure actual deflection of the structure).
'Fast Jet' combat aircraft are usually better instrumented for vertical 'G' forces to ensure crew awareness of wing loading (lower stall speed at high G) and the 'G' force they themselves are experiencing. They still have fatigue meters though.