If all else fails you could try scanning each page individually and then sending four separate emails/attachments. Not a very elegant solution, but it's worked for me in the past.
On another occasion I reduced the scan resolution to give a file size just below the attachment limit, but of course picture quality suffered. Probably not an acceptable option as your file size is so much greater than the limit.
Last edited by spekesoftly; 27th Aug 2018 at 09:04.