I'm using PPPoA with a Sky ADSL connection and an MTU of 1492.

However, I've been having problems with an EE Signal Box and I've been asked to change the MTU to 1500. I had a look and it looks like I'm limited to 1492 in the router settings - why would that be if I'm on PPPoA?

Hi again, i don't know why, PPPoA should allow 1500, but try the telnet command if works (assuming in the settings you have set PPPoA)
wan mtu 1500 (this is for wan 1)
for wan 2 is: wan mtu2
to check if worked or the status, wan mtu ?
or wan status ?
If will not work then sorry i don't know why PPPoA is limited on drayteks

Thanks, I've set it to 1500 on the off-chance that it fixes my problem.