It is vfat, and it isn't mounting read only, as root has full permissions.
I'll have to check to confirm (I'm on one of my other machines at the moment), but I'm around 99% sure I've given the relevant user group permissions in fstab, as I am able to mount it as my main user account, not just as root.
EDIT: As I thought, the relevant lines are as is -
/dev/sdb1 /mnt/external vfat defaults,users 0 0
and from /etc/group:
where deadpool is my main user account...
EDIT: Wait, now I might be seeing it, does 'defaults' override the 'users' command? deadpool is also a member of plugdev, which if I recall correctly automounts all applicable volumes...
LAST EDIT: Bingo, I've got it working. Thanks for the push in the right direction, but it's definitely rewarding when you figure it out yourself.