We've had some more information now. It looks like it's our router that is the problem. We have a Cisco 1841 and we've found a few articles and forum threads suggesting that it is barely compatible with ADSL2+. Apparently there's a couple of firmware updates that improve stability. Cisco have end of lifed the router and the WICs and are now recommending we upgrade. over £700 for a new router and over £900 for two new WICs.

Pathetic really. I bet there's still some BT Frogs out there working quite happily. We're going to try and push our ISP to update the firmware (they have a service contract) and better yet by the end of this year or before spring we'll have a fibre based service to the office park.

http://stewartandrews.wordpress.com/2012/06/28/cisco...
and
https://supportforums.cisco.com/docs/DOC-6183#/?page=2

Edited by Andrue (Tue 30-Oct-12 17:59:05)