Draytel issues

Hey guys

Using a Grandstream 486 (Revision 2) ATA behind a Linksys BEFSR41 router, I
*used* to be able to use Draytel no problem. Now, my incoming PSTN number
is rarely recognised by the telecoms operators, and when it is, I go
straight to voicemail. I am also no longer able to successfully make any
outgoing calls. There have been no configuration changes or firmware
updates. I've never had to use a proxy, STUN server or port forwarding of
any kind. In fact, even when using these extra configurations, Draytel
still does not function (even though the ATA shows REGISTERED).

Interestingly, my sipdiscount account works perfectly, which makes me sure
it's a Draytel issue.

Anybody else having issues with Draytel?