Edit Mount Points

I have an Odroid Cloudshell2, with 2* 2TB disks and an SD card.
I would like to edit the mount points for the hardrives, but they don't seem to have entries in the fstab file. I have even tried re-image the SD card from a new default image and the hard drives still mount in the wrong place.
/dev/sba mounts in /media/odroid/Database
/dev/sdb mounts in /media/odroid/Files

I would like them to mount as follows:
/dev/sda mount in /mnt/data
/dev/sdb mount in /mnt/files

The idea is I place all my mysql databases in /mnt/data, and I create a nas system, that I have not yet selected, with all the content in /mnt/files

The fstab files only has the following lines:
UUID=e139ce78-9841-40fe-8823-96a304a09859 / ext4 errors=remount-ro,noatime 0 1
LABEL=boot /media/boot vfat defaults 0 1


Because they're being automounted by, umm, whatever this week's rewrite of udev is called.

You've aleady answered the question yourself, really. You need to create entries for them in fstab so they get mounted there instead.