NX534
The confusion arises because both c/n 458 and c/n 271 were registered PH-POL at some stage. PH-POL (1) c/n 271 was cancelled following a landing accident in 1955 and it was replaced by another ex Netherlands military Auster III (c/n 458) PH-POL (2) later the same year.
Austers in the NX serial range served in many theatres of war and several were transferred to the air forces of the Netherlands, Greece and Australia.
Another Netherlands Auster currently in an advanced stage of restoration is NX537 c/n 462 (PH-NIN). I am not aware of any others in the range that are extant but one never knows what might emerge one day!