Not the easiest to get working, but simple enough to get your head around

Core pre-req requirement not mentioned:
FPING

Ubuntu16 instance had to modify the FPING path to usrinfping (not usrsbinfping)
Also had to modify the grep string check for the latest strongSwan tunnel check:
ORIGINAL: tunneltest=`$IPSECBIN status | grep -e “IPsec SA established” | grep -e “newest IPSEC” |grep -e $CONN | wc -l`
UPDATED: tunneltest=`$IPSECBIN status | grep -e “ESTABLISHED” | wc -l`

Suggest using full path in GATEWAYLIST variable instead of relative path and just a filename.

Works effectively once tweaked for the deployed environment.