This was already done, it has now updated, cache or something?
it was due to cache.
The email logos remain sellacious though, how do I change these?
To change the logos in emails, you have to modify/change the email templates as per your need.
Login to your sellacious BackOffice => Email Templates => Click on the name of Email Template to Edit => Click on "Edit in WYSIWYG" => Click on source code icon "<>" of WYSIWYG Editor => change the image src path of logo as per your need. see screenshots.