Widgets appearing within wiki instead of on sidebar

I've just updated to the latest version of wiki and as a result, on any wiki 'page', my sidebar widgets are appearing below the wiki within the wiki content area (same for 'discussions' and 'history') - however they return to the sidebar where they are meant to be when you select 'edit' or 'create new'

I've disabled & reactivated the plugin, I've also disabled the other two plugins I have running (Sidebar Login & WPMU DEV Dashboard) and it makes no difference.

You can see what's happening at http://www.mariposa-test-site.co.uk/dbsl/wiki/knowledgebase-resources/

Can you help?