andynz: Thanks guys, lots of help there understanding the ins and outs of Xtra broadband. I finally got to the bottom of the problem today. I dropped the SMC7904 back to ADSL1 and it locked quickly every time. I did this after speaking to the tech support at Computer Dynamics who supplied it. They told me that when Telecom rolled out ADSL2 not all the DSLAMS were configured in the same way so you can find some brands of modem will work with ADSL2 in some areas but not others and visa versa with other brands of modem.
Any comments from anyone on that scenario? Are there issues with inconsistency in ADSL2? I can believe that could have happened.
Using ADSL1 still gives 8-9mbs connection so fine for the application.
Glad you got it up and running... As for the ADSL2+ inconsistencies - could you please pm me the name of the person you spoke to at Computer Dynamics and I'll see if I can see what they were referring to.
While there are some small differences, there shouldn't be any ADSL2+ routers that totally fail to connect. (apart from some higher layer known issues unrelated to ADSL chipsets - and even then, I'm only aware of one negotiation oddity with some Cisco gear and some Telecom gear)...
The question I would ask is why is Computer Dynamics selling an ADSL2+ device that can't connect with ADSL2+ equipment from the largest provider in the country! They may very well not be precisely correct.
Cheers - N