Hello Simon,

The login credentials which you provide doesn't seem to work for me so I can't really test this but based on your description provided, I am assuming that:

1. It could be due to Admintools preventing the ajax calls from being submitted

or

2. Your web hosting company has some security mechanism in place which is detecting this as a false positive report. The last I recall, it was mod_security. After the hosting company added some exception rules in the mod_security, their site was saving just fine.

or

3. There is a system / content plugin which is messing with the saving.

Could you check if either one of the above is in place? If you need me to troubleshoot this, could you edit your post and include the ftp and back end access to the site?