I've now made these updates to Lemmings, Covox Lemmings, Prima Lemmings and Extra Levels official, as V1.47n-D supports them properly. I reuploaded slight modifications; the only change from those that I uploaded before is that they won't create a compatibility warning on V1.47n-D.
Please be aware that these four, in the latest version, will only work on V1.47n-D (or V1.48n experimentals). The special graphics levels, at the very least, will not work on V1.47n-C2 or earlier. If you report a problem with these latest versions and it's clear you're trying to run them on V1.47n, V1.47n-B, V1.47n-C, V1.47n-C2, or (god forbid) V1.43n-F, I will not even bother to respond. Just to be on the safe side, be sure to mention that you're using V1.47n-D (or a V1.48n experimental, if applicable).