Well, all credit to BT, the ADSL was switched on, the modem and software worked out of the box and rather painlessly we are onto broadband.
One thing that did alarm me a bit was the high volume of pings from the firewall software that reached over a 1000 in the first hour until I turned the message box off. Most came from BT-registered users, so I shot an email off the snipped-for-privacy@bt.com to burn their ears a bit.
We haven't received the ADSL Ethernet/USB modem that we expected to be here by now, and that will give us access to the web from all the PC's on the network, and having web access continuously means that you don't have to worry about the phone bills when all of you are bashing away!
Very pleased, and glad we bit the bullet and got it working.
Peter