Help. Plusnet Broadband and Draytek 2860 Router Settings

Having a few issues. I�ve been through 3 Plusnet hub one fibre routers and then a friend advised I get a Draytek 2860. I�ve got one and inputted the settings I thought I should put in. It�s working but my son is complaining that his xbox is laggin and throwing him off. Can anyone help why this would be?
Thanks in advance.

Also how to I add screenshots of the settings here?

I have a Draytek 2925 on which we experienced odd performance issues if the Draytek hardware acceleration was enabled. Might be worth testing with that turned off to see if that helps.

You would have to upload to a picture hosting site, then post a link to that page ...

Look at FIREWALL/Defense Setup - the SYN/UDP/ICMP flood defense, they sometimes kick in and stop things for a few seconds, I normally would only tick Enable DOS Defense, and leave the rest un-ticked.
The best option I found with Drayteks is to use their syslog tool, best option is to use the PC based logger and send logs to it, its just easier to use than the built in option, which is goto System Maintenance/Syslog and enable.
Then use the Syslog explorer under the diagnostics menu - you should see the IP/MAC addresses of the Xbox and see what if anything is going on that might be blocking it.
If something is being blocked the syslog will tell you.