I am sorry, but I can't understand your question.
What is the "bbb small logo in the page header" you are referring to? The only logo I can see is the one on the first page of the preloaded presentation. If this is what you mean, then you should talk to the moodle admin. They can change the default "Pre-upload presentation" of the bbb plugin. The path (for the admin) is 'Administration / Plugins / Activity modules / BigBlueButtonBN' page - 'Configuration for "Pre-upload presentation" feature' section (near the end of the page).
What is the "bbb small logo in the page header" you are referring to? The only logo I can see is the one on the first page of the preloaded presentation. If this is what you mean, then you should talk to the moodle admin. They can change the default "Pre-upload presentation" of the bbb plugin. The path (for the admin) is 'Administration / Plugins / Activity modules / BigBlueButtonBN' page - 'Configuration for "Pre-upload presentation" feature' section (near the end of the page).