If you want free 192 operator calls from BT, just ring 198 and ask for a form for free 192 calls for registered disabled people.
BT will send you a simple form, half of which is completed by you and half by say your doctor, vicar, social worker or someone who can vouch for you.
Send the form back to BT and in about a week you will receive a card with a pin number on it. Every time you need a telephone number you phone 198, quote your pin number and surname and request the number you want. Free!
You will be surprised how much you can save over a year. Good luck. Peter.