Unless I am looking in the wrong place I have no MDR key. This install was done originally using a 1.2 exe installer and updated to 1.31 by copying in the topomap folder ( I had a faulty connection to the internet at that time). I have basically a clone of it still running on the laptop. It has no entry other than 'trip and waypoint' under families. In the entry for NTDBData under products there are only keys for BMAP, LOC and TDB plus the normal default
I do not know now what registry entries were made on the first update attempt but I do know that it would still work after with the old topomap directory restored
If it helps, now that all is working well I see that the tiles that were originally working were the ones that remained small, the newer large ones showed only numbered highways and nothing else