<<< I have gone to control panel, clicked on BT Voyager Utility to tick box to show icon, but keep getting the message 'internal configuration inconsistent restart computer to fix problem'. >>>
When you go into the Network Connections folder, right click the Wireless Network Connection and select "View Available Wireless Networks", is it Windows own software that scans for networks or the third-party software supplied with the adapter?
If it is Windows, this means that the Wireless Zero Configuration service is running which will disable the other software.
If necessary, the Wireless Zero Configuration service can be stopped by right clicking My Computer, selecting Manage and, in the window that opens, clicking the [+] beside "Services and Applications" to expand it. Highlight Services and, in the right pane, scroll down to Wireless Zero Configuration. There should be a link to "Stop" the service or you can double click the entry and click the Stop button.
<<< Also, BT Voyager 2091 does not show up in the 'add and remove programmes'. >>>
You don't *INSTALL* a router in a PC so there is no program to uninstall. A router is a network device that you connect to by ethernet, either with a "wired" connection or "wirelessly".