Id' like to thank the tech support staff at XNet.
While getting a sky box installed the contractor had cut the phone line to put a phone jack to a new location.
With the router on this caused a short which for some reason altered the PVC setting to disabled (why I have no idea).
I didn't realise the Sky contractor had cut the phone line to add an extension so I called XNet and they patiently went thru diagnostics and then had a Telecom (Chorus) guy check the line.
The most amazing thing was a Chorus tech rang to ask how it was going, this was a first, so maybe things are improving because of the split.
After trying an old router (ADSL) I could get internet access but the speed was slow eg 2Mbs compared to (11Mbps) on AG310(ADSL 2+).
I tested the line voltage and it was 4-5v so I suspected something was up as it should be >45v.
After crawling under the house and seeing the Sky Contractors efforts I cut out their efforts and rejoined the wires.
Heh presto full speed and everything working fine.
Moral of the story - Only cut one wire at a time, don't trust every crimp to be good. Use a voltmeter.
So I owe a few more beers to the XNet Techs, these guys are very good.
PS on a side note I've been recommending XNet to alot of friends and family. One sticking point is transferring email providers. I know of portable numbers, how about portable email addresses? Once you've got a couple of thousand business cards printed it's very hard to change ISP's.