Using luci-app-nlbwmon to monitor per device traffic

I just found a great new monitoring package

Looks good. I have been struggling to get YAMon running on a router running LEDE without USB by trying to install to an NFS share without much luck.
I have now re-installed the latest LEDE on the router and installed the nfs client packages.
I have mounted an nfs share manually from the router and set up luci-app-nlbwmon to use the NFS share for the database directory to store the "one file per accounting period" for luci-app-nlbwmon and set "Commit Interval" to "60 s -- commit every minute, useful for non-flash storage" and it seems to be working a treat.

I am not that familiar with WRT/LEDE mounting options in fstab though.
Any advice would be appreciated on how to configure fstab for nfs mounts to persist after reboot of the router.

OK, To partly answer my own question and to give some detail of what I am doing in the hope of some assistance.

I have created the directory structure
on the router
I have used /srv/remote/[serverdirectory]/nlbwmon for the luci-app-nlbwmon database directory

I can manually mount this with the command
mount -t nfs -o nolock serverIP:/srv/nfs/[serverdirectory] /srv/remote/[serverdirectory]/

ls /srv/remote/[serverdirectory]
shows the file structure on the server including my nlbwmon directory there
umount /srv/remote/serverdirectory]/
unmounts the nfs share
if no nlbwmon directory exists then the next nlbwmon commit cannot add data to existing file as nlbwmon cannot write its commit to a path that does not exist. The next time the nfs share is mounted nlbwmon commit seems to add data to the file OK.

When adding the following to /etc/fstab
serverIP:/srv/nfs/library2/ /srv/remote/[serverdirectory]/ nfs nolock 0 0
and running the command
mount -a
the nfs share is re-mounted and nlbwmon commit seems to add data to the file OK

However, the share does not mount automatically on reboot of the router.
I have run /etc/init.d/fstab enable.
but still the share does not automount on reboot.
What am I missing?