OK, back to Cambodia for a minute. Not sure if this has been identified already, but found this pix of a Bayon Temple gate
that looks very close to Matt's gate. The 2004 pix appears to be a view of the gate from the opposite side (outside).
Note the "collapsed" stone in the opening above the passage. OK, the 2004 pix has some vegetation, and the opening allows visitors to pass thru, while in Matt's 2008 photo the gate is fenced off, and no vegetation. Things change in 4 years, maybe.
Too bad we can't see the other side.
Close enough, huh?