Two external phones on same connection

[eagle2]

All fixed....

Main problem was using a Basic Router provided by Sky in the external office...

Installed a Netgear Modem and a Open Source Asus Router with DD-WRT loaded, Fixed all the NAT problems of only being able to have one phone fully working.

All this is about the remote router -- the new router you installed is obviously SIP ALG compatible and is handling SIP/SDP/RTP packets correctly.