i think you press 141 then dial the rest of the number you are calling. your operator can give you more info. or if you are on bt you can arrange to have your number withheld every time you dial
Thank you everyone. Very helpful. Ethel, not sure about skype. Have a friend who uses that and it seems to have a terrific echo which is quite off-putting. Don't know if that's normal or if it's because the friend is in Australia ! !
But thanks anyway.