I tried that but without luck. However, I retraced my steps with regard to swapping the NIC and spoofing the D-Link modem and, shock horror, it works! I must have entered a wrong password or similar.
Many thanks, though, for your suggestion. If any other E-smith fans want to use Demon with this D-link device then the process is as follows:
1. take your "external" NIC from your e-smith box and put it in a windows m/c in order to configure the modem as a PPPoA connection with username and p/word etc.
2. replace the NIC in the e-smith box.
3. configure e-smith to connect to a DHCP server and send the network (mac) address as its identifier for this purpose.
4. Test internet connection ...
Cheers.