Just an update folks. I've done a complete re-build of the MySQL server due to problems with the information_schema not wanting to be repaired (ah the joys). After reconfiguration, importing of the DB backups and setting up scheduled backups, all is now working properly again.
I've checked the Avant Browser forums and the Chinese Avant Browser forums and cannot see any issues, so if you notice any problems, please do let me know and I'll look into it.
And a note to the MySQL dev's (or those that work on the installers), the installers for the latest version of MySQL do not work (kept resulting in "setup was interrupted" errors, even when MySQL was uninstalled). Had to use an older installer to get it installed, then do a manual upgrade using the no-install .zip file. Might want to look into that ;o)