Trixbox and Inbound VOIPTalk IAX Issue

Hi

I have a trixbox working with analogue cards and phones which works great.

I have just got an IAX line from voiptalk (who's support is non existant, online docs 3 years out of date) and managed to get outbound working fine, but I cannot get inbound to work.

I have forwarded the ports through the DG834G router and setup the IP address at voiptalk, however when I call the line just says failed. I look on the router logs, NOTHING! Is this being blocked at the ISP? (BE Broadband in the UK). I have also put the Trixbox into debug... NOTHING.

Any help greatly appreciated at where this could be going wrong!

Cheers

Dave