Bob906 when you called 1471 and got the number that rang you, you have to make a note of the number, hang up and then start from scratch. i.e. 141, then the number that called you, this will withold your number.
From a mobile, go to SETTINGS - press select; scroll down to CALL SETTINGS - press select; scroll down to SEND MY CALLER ID - press select; use your up and down button to highlight either YES or NO - you need to highlight NO - press select. You can press your red hang up button. All further calls will not show your ID.
Obviously, reverse the instructions to start showing your ID again on future calls.