I've cut the filter open and there's absolutely nothing metal in there.
I'd have to reassemble the engine and run it to test the
oil pressure, so it makes no sense to me to not replace the
oil pump while I have it out.
If, when I've fitted the new pump it still misbehaves, I'll check the pressure with another gauge.
I've spun the pump on the bench with an electric drill and it doesn't sound particularly healthy. There is a definite knock and a tight spot.
Paul