After a lot of hairpulling and asking smart people for help (Mark Cederholm, Kirk Kuykendall) I have a working python script which searches a file geodatabase and changes the AliasName of the matching feature classes from the incomprehensible BS_1370009_2 to the human friendly Residential Area. It does the same for a subset of the attribute names.

AlterAlias.py can be nabbed from my bitbucket canvec repository. It relies on python+arcobjects (necessary portion of which is bundled as parco.py)

I took the route of changing the aliasname instead of the fc_name to make it easier, I hope, to automatically incorporate the twice annual canvec updates.