I've done as requested like I did when I first uninstalled Memphis but still, when I run Live update it downloads KMEM very slowly file by file. There are no references to KMEM or Memphis in my registry, any ideas?
The registry doesn't have anything to do with this. The Live Update thinks KMEM is still installed, because the folder that contains its objects is still there:
Addon Manager\Simobjects\Misc\FSDT_KMEM
This folder will surely be removed if you ran the scenery uninstaller so, it's not supposed to be there. However, if your original KMEM was MIGRATED from another previous installation using the old installers (the ones that used to install INTO the sim), its uninstaller won't remove anything (uninstallers remove only files from their original locations).
Which is why I said: "It's best if you reinstall them both, and this time really run their Uninstaller", because reinstalling would create a new updated uninstaller. Of course, you must use the latest installers.