SSRS R2 Report Builder icon appearing in sharepoint web part

Hi,

We have just migrated our SSRS reports from 2008 to 2008 R2. We have noticed that the Reports server url we specify in a sharepoint webpart has a Report Builder icon in the header. How do we get rid of the option for the users to access Report Builder? and so stop it appearing in the webpart

All the users are part of the System User role,

see example below,

thanks,

Stu Disney