Thank you both for responding!
I did try and move a few directories from / to other directories, & created a fstab entry. However, did not free up much space.
The .journal file is actually just over 3GB in size, so I know if I can move or delete it, that would solve the problem. (just wasnt' sure if it was a critical file)
This is a high volume webserver - so after hours, I will attempt to revert to the ext2 file system and see if I can delete the .journal file that way.
Or, seems the safer route might be to resize the .journal file.
Again, many thanks.