Thank you all for the interest and the messages of encouragement. It was tough going through my old records on this topic. I have expanded the sections back to before independence (though information is scarce) and updated some of the information that I initially wrote in light of new materials (e.g. Kwala in Kuala Lumpur).
It will never be complete as there will be some errors lurking around being kept by private collectors. However, I am encouraged by the interest shown on this topic. If you have news, information, materials and such to share, I would really like to feature it. Of course proper acknowledgement will be given.
The page is a doubled edged sword. On one hand new collectors will know the gems they are holding and they will also not fall for hype (e.g. the “x” in the Royal Visit issue). On the other hand, some sellers might take the chance to hike up the price with the new information being written here. I advise you to shopwisely and pick up the real gems. Many errors are common and do not command a premium.
So here it is, the expanded and updated page: https://myfdc.wordpress.com/errors-and-unissued/
HINT: Easier to read a printed page (in colour)!