I've just moved the site from one VPS to a new VPS using the Plesk migration tool, so I'm not sure if its a problem with plesk or the new VPS setup.
When the site was moved and I found some features/ sections not working I noticed that odd files and directory's were owned by Apache. Changing these back to the correct user/group cured the problems.
But now any files created by my site, my blog for example, are created under the user and group Apache which make them unusable unless I manually change user and group.
Any help advice thoughts greatly appreciated.