These two trogons, this one and the Red-naped in the other picture, were actually seen in the same place within a couple of minutes of each other. I was with another birder at the time, just a someone who I met earlier and birded with a bit, and we naturally assumed at first that these were a pair of the same species, this being obviously a male Diard's and the other being less obvious to identify given the view only from behind and of a female.
However on immediate review of the pictures, the second one didn't look right for female Diard's and we suspected Red-naped which was confirmed as the other birder sent his picture to a local guide who he had been birding with earlier who said it was an immature male Red-naped.
So clearly the lesson to be learnt is always hire a local guide to ID everything for you so you don't have to bother. No that's not right, I mean, the lesson is to always check your IDs carefully and don't assume the obvious!