Please help can not log in to Sipgate

[#1]

I contacted plusnet a few days ago and as they no longer offer voip I signed up with Sipgate.
I am using a Grandstream GXP1450 SIP phone and have made sure this has the latest firmware. I can make the phone work with an Asterisk pbx server within my home network, but I am unable to connect the phone to sipgate, it will not register.
I have been looking at my router a Technicolour TG852N version 8.4.4.J (seems to be the latest  for it).
I have tried port forwarding, using stun settings, Upnp on/off and can not get the unit to register.  In the end I ended up doing a factory reset on the router to get back to  the start.
Can anyone help that has the same 852n and an account with Sipgate tell me what they had to do?
Cheers
Adrian
It is now registering, not sure what I have done, but with no mods or changes to the router think I was possibly missing port 10000 from the stun server?

[#2]

OK problems still exit, I can call out but not receive calls, they all show up on my account as missed calls when I try, back to messing around.
Adrian

[#3]

You'll probably need to disable the SIP ALG on the TG582n. See this thread http://community.plus.net/forum/index.php/topic,117680.0.html/