IPv6 with Proxmox

TL:DR I have a $35 dedi from Datashack. Trying to figure out how to get IPv6 working.

Currently I am using proxmox in routed mode? (Whatever it ships in default)

My /etc/network/interfaces(on the node) looks like this:

auto lo
iface lo inet loopback

auto vmbr0
iface vmbr0 inet static
        address 199.168.102.XX
        netmask 255.255.255.248
        gateway 199.168.102.XX
        bridge_ports eth0
        bridge_stp off
        bridge_fd 0
iface vmbr0 inet6 static
        address 2604:4300:Censored:36:0:0:0:0002
        netmask 64
        gateway 2604:4300:Censored:36:0:0:0:0001
        bridge_ports eth0
        bridge_stp off
        bridge_fd 0

Currently, I am getting a lot of:
root@server:/# ping6 ipv6.google.com
PING ipv6.google.com(da-in-x63.1e100.net) 56 data bytes
From 2604:4300:Censored:36::2 icmp_seq=2 Destination unreachable: Address unreachable

Anyone have any ideas? I know several of you lovely folk own similar boxes from Datashack, have you got IPv6 working?

-(I'll probably be opening a series of these "Proxmox: help me, I suck threads." I promise to write a lovely howto based on my notes very soon.)-