God looks after fools and the ignorant, or else I was lucky. I simply upgraded to LR 5 and there my catalog was, pristine and intact.
Hmmm! when I upgraded from 3 to 4 it was part of the process to accept that the catalogue would be copied and the LR 3 one left intact........ and I have a Lightroom 3 and a Lightroom 4 catalogue file with their appropriately named preview catalogue files. So is LR 5 so very different that we can end in the LR catalogue (potential) confusion that is refered to in the video???
Note ~ this is on W7 Pro SP1 not a Mac