P was XV134 click on the serial for the photo on the demobbed link.
M was XR595
For more and the XV134 picture
http://www.demobbed.org.uk/aircraft.php?type=957
I cannot find a shot with the M on the nose but try googling the civi reg for it or the serial no.
But images of it show a lump on the nose so maybe it was removed later, it is on the tail though
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