The locations of the original map was mostly taken from the official UNESCO website via the Excel file on their website
. That was enhanced by some of my own work in correcting obvious mistakes, filling gaps. Then I posted it here and we filled in some of the other gaps, I've incorporated some but not all of those corrections, as we then switched focus over to nfmungard's approach. The files that formed the basis of his approach incorporated all of the corrections we posted (from what I recall anyway, sadly my masterfile detailing it was on a laptop that was stolen).
My intention was to go back and incorporate all of our updates and highlight for any gaps, alas events got in the way and then I lost a chunk of work during the aforementioned pilfering.
I'm still planning to get back and update the current file as I find it really useful to use, but it isn't as tailorable and 'live' as nfmungard's suggestion.