Solved - installed usbmount and copied the following udev rule, named 69-local.rules, to /etc/udev/rules.d:
# Leave sda to fstab
KERNEL!="sd[b-z]*", GOTO="media_by_label_auto_mount_end"
# If booted from /dev/sdb with home on /dev/sdb5:
# KERNEL!="sd[c-z]*", GOTO="media_by_label_auto_mount_end"
# KERNEL=="sdb5", GOTO="media_by_label_auto_mount_end"
# Handling only ext4 partitions; better leave this commented out
# ENV{ID_FS_TYPE}!="ext4", GOTO="media_by_label_auto_mount_end"
# Import FS info
IMPORT{program}="/sbin/blkid -o udev -p %N"
# Get a label if present, otherwise specify one
ENV{ID_FS_LABEL}!="", ENV{dir_name}="%E{ID_FS_LABEL}"
ENV{ID_FS_LABEL}=="", ENV{dir_name}="usbhd-%k"
# Mount options
ACTION=="add", ENV{ID_FS_TYPE}=="ext3|ext4", ENV{mount_options}="rw,nodev,nosuid,relatime,acl,uhelper=udisks"
ACTION=="add", ENV{ID_FS_TYPE}=="vfat|ntfs", ENV{mount_options}="rw,relatime,utf8,gid=100,umask=002,uhelper=udisks"
ACTION=="add", ENV{ID_FS_TYPE}=="hfsplus", ENV{mount_options}="rw,nosuid,nodev,uhelper=udisks"
# Mount the device
ACTION=="add", RUN+="/bin/mkdir -p /media/%E{dir_name}", RUN+="/bin/mount -t %E{ID_FS_TYPE} -o %E{mount_options} /dev/%k /media/%E{dir_name}"
# Clean up after removal
ACTION=="remove", RUN+="/bin/umount /dev/%k", RUN+="/bin/rmdir /media/%E{dir_name}"
# Exit
LABEL="media_by_label_auto_mount_end"
Many thanks to the archlinux people - found the original of this on
https://wiki.archlinux.org/index.php/Udev
"Safely remove drive" will work with kde, but it did not work in GNOME.