I've worked out how to upload the file by compressing the mysqldump further so that phpMyAdmin could handle it. I used a tool called Gui Tar http://www.macupdate.com/app/mac/14503/gui-tar which compressed the file down to 12MB from 65MB so could now be handled by phpMyAdmin from within my host's Control Panel. I compressed it as .bz2 file which uploaded just fine!
Hopefully this helps someone else.
