Didn't know that, no. But there are too many threads, some python/perl and it was all very confusing.
But in the end I found it was simplest to go back three steps (images) and start from there. All went well. I still don't know what I did wrong the first time, as I reproduced my steps from my notes - maybe not in the exactl order though, so it is possible I've blocked myself from being able to migrate any more accounts to this system
It could also be a munged file as as I was working from a clone of a clone of a clone.
What I'm liking is being able to run all the mod_sec rules (at least those enabled by default at any rate). But there's not been any load on the server so we'll see if we end up back with the dreaded segfaults/bus errors that I was getting in EL4 as a result of that PCRE or whatever it was bug.