ltk19 I don’t think there is a way to do this. Make sure only display templates with data they are allowed to access is available to them.
If this isn’t enough, then letting them access this data through the cataloguing side probably isn’t what you need and you should install Pawtucket. This way you have full control over what they can see and do.
Only other option is to copy the theme and change the views to not show the download buttons for the researcher type user.