When we have had problems it was easier to dump database to sql statements, drop database, recreate with media wiki setup with all correct settings and restore the data without drop table instructions.
Sounds sensible. Thank you.
Unfortutately, as a consequence of one of their changes, data has been partially lost (apparently only redirects and a few templates and images) and I think several tables are corrupted in the sense they contain data which shouldn't be there, so I'm even considering an export and then and import (with history, of course) for articles and the like, and only resort to the database for users (this table seems ok) and the like (just brainstrorming). <sigh>
Javier