[RESOLVED]
Was running on 3.6.4 firmware. The Samsung Galaxy Note 10.1 would not pick up the bound IP address from the DHCP table. Restarts of both router and Samsung made no difference.

Found firmware 3.6.6 and worked instantly. Someone else has mentioned a similar issue elsewhere but thought I should mention it.

Can be found here but isn't on the downloads section of this site. No idea why as it's dated November 2013.

ftp://ftp.draytek.com/Vigor2920/Firmware/

thanks for the update ... the date 26/11/13 is because at that specific date the firmware 3.6.6 was out (released) at the main draytek ftp web & at the main headquarters draytek download page was a day later 27/11/13
http://www.draytek.com/index.php?option=com_jumi&view=application&fileid=15&Itemid=583&lang=en
so the 3.6.6 firmware is almost 5 months old