In case any one is interested figured out how to do per vdom snmp monitoring for CPU, mem etc
Took a bit more than finding a standard OID value, as each VDOM needs it own OID value.
Below are the main OIDs then add on the end .1 for VDOM 1. Ok so you need to find out which VDOM is number one.
I found out that you can't use the diagnose sys vd list command as it doesn't give the right info. Your best option is do a MIB walker against the firewall and this will return the vdom name against the OID 220.127.116.11.4.1.12318.104.22.168.1.1.2
ie SNMPv2-SMI::enterprises.12322.214.171.124.126.96.36.199 = STRING: "CUSTOMER2" so you know you can then use OID 188.8.131.52.4.1.123184.108.40.206.220.127.116.11 adding the 2 on end as you know this is VDOM 2 now and name your graphs.
We used a standard SMNP customer OID sensor in PRTG to graph the CPU %, MEM % and session rate values