Windows 7 x64
Draytek Vigor 2860n

LAN => General Setup => DHCP Server Customized Status

What DHCP option do I need to use in order to exclude a range of IPv6 addresses from being used, or allocated, by DHCP?

I am aware that a full list can be found here (IPv4): https://www.iana.org/assignments/bootp-dhcp-parameters/bootp-dhcp-parameters.xhtml

...and here (IPv6): https://www.iana.org/assignments/dhcpv6-parameters/dhcpv6-parameters.xhtml

...but have been unable to find the actual option that will allow me to specify a range of addresses to be used, or not, by DHCP.

Go to LAN >> General Setup then select "Details Page" button for LAN 1, all in there .