Hello, this issue has now been resolved. I contacted the hosting provider and this is their response. All OK now. Thanks Dennis
Thank you for coming back to me with those detailed steps, this helped in confirming the cause of the issue you have reported.
The issue preventing changes to the Web Application Firewall settings in Akeeba AdminTools was caused by ModSecurity, which is part of our server-level security setup. When enabled, ModSecurity can sometimes block certain actions within Joomla’s admin area, in this case, saving changes to AdminTools’ configuration.
Disabling ModSecurity temporarily allowed the changes to be saved successfully. Please note that ModSecurity is enabled by default across all hosting accounts for security purposes, and we’re unable to modify these settings on a per-user basis.
If you need to make further changes to AdminTools in the future, we recommend temporarily disabling ModSecurity while performing those updates, then re-enabling it afterwards to maintain site protection.