Have you tried updating the firmware? That's probably going to be the first thing Draytek Support will ask you to do if you send in a ticket.

Just to update on my ticket, Draytek have sent over the 4.4.2_RC firmware which seems to have solved my problem, may be worth getting in touch with support if the issue still persists.

It does sound like a strange problem you're having though, maybe a reset and re-config?

I have done the reset issue but it still persists.
do you have any contact details for Draytek?

Many thanks

It's fairly easy to find....

https://www.draytek.co.uk/support/contact-support