OK - sorted now (minus a few fingernails tho! - thank god for the backup I took with tar last week!)
Heres how:
1) make the new partition, & format with mkfs. (in my case hda3)
2) mount the new filesystem in /mnt
# mkdir /mnt/new
# mount /dev/hda3 /mnt/new
3) Go to single-user mode so that there is no rw activity on the directory during the process (could be messy...)
# init 1
(re-enter root password - wont work via ssh... gave me a shock!!)
4) Backup data in var only (not the /var directory itself)
# cd /var
# cp -ax * /mnt/new
5) Rename the /var directory (to make sure this has worked before deleting it!)
# cd /
# mv var var.old
6) Make new var directory
# mkdir var
7) Unmount the new partition
# umount /dev/hda3
8) Remount it as /var
# mount /dev/hda3 /var
9) Edit /etc/fstab to include the new partition, with /var given as the mount point, so that it will be included in the filetree automatically at boot.
& when y'r sure that alls well, delete var.old...
Bingo.
