Hi I f,
"I hardly dare ask this, after the discussion, but as a baffled newcomer..."
One thing to keep in mind (and sometimes it's difficult) is that whatever the reaction here, there are no 'stupid' questions, except the ones that do not get asked.
Your templates are located at:
username (the house icon) > Library > ApplicationSupport > Iwork > Pages > Templates > My Templates
For Lion users, start in the Finder, click the Go menu, then press and hold the Option key as you choose Library.
That will put you in your User Library. After that, follow the rest of the path above, open the My Templates folder, then delete templates as you would any file:
Click on the file to select it, then either drag it to the Trash OR press command-delete to move it to the Trash.
Regards,
Barry