DHCPv6 Relay on M5300-28G3

Hi All, I've having a bit of a problem testing an IPv6 deployment on a stack of M5300-28G3s, specifically I can't seem to get DHCPv6 relaying to work. I have the following:

• A couple of routing VLANs with IPv6 prefixes assigned
• All clients on the VLANs are receiving their assigned prefixes and generating their autoconf global addresses
• IPv6 routing is working happily on all VLANs
  • Both inter-vlan internal to my site
  • And external to the real world
  • ping6, traceroute6 etc are all happy
• On one VLAN I have a DHCPv6 server
  • On this VLAN DHCPv6 is working perfectly
  • Name servers are distributed
  • DHCP fixed IPv6 addresses are allocated
• DHPCv6 does not work on any other VLAN

I think that I've read the manual correctly in assigning the DHCPv6, I've been using:

ipv6 dhcp relay destination IPv6_Address_Of_Server 1/0/1

A possible concern that I have is with the relay address of the server. The DHCPv6 server is not physically connected to this stack but is down a LAG on another switch. In that situation I think I should use the VLAN address as the interface? However, my interpretation of the manual is that specifying the IPv6 address of the server should be enough. Any suggestions? Thanks in advance, -pete