Thanks guy's
Thought i was being silly and missing something
I think the best thing to do is setup the alerts for the customer on the NIC's and VM's also to maybe log a call with VMware about the NIC's going offline as it was weird, both NIC's showed as up from the config screen but you was unable to ping the default gateway from any of the VM's connected to the vSwitch, forgot to test to see if you could ping another VM on the same vSwitch also if you clicked the CDP icon this showed no info. Once the host was rebooted you could ping the gateway and see CDP
Thanks again