Sorry. Yes my first description is of RING back.
The 1471, press 3 is CALL back.
RING BACK
When you hear a busy tone, simply dial 5. A recorded message will tell you if your Ring Back request has been accepted. If it has, you can hang up and your phone will keep trying that number until it's free. When it is, your phone will ring and you'll be connected. Ring Back will keep trying a busy number for up to 45 minutes and you can request up to five Ring Backs at any one time.
Ring Back costs 15p (incl. VAT) per use, or £1.75 (incl. VAT) per month for unlimited use and is also available as part of a Calling Features Pack.
Caller Return (I assume same as call back)
1471 Call Return service tells you the last number that called - unless the caller witheld their number by dialling 141 before dialling your number, or the call came from a switchboard extension number. 1471 Call Return also lets you return the call straight away, by simply pressing 3. 1471 is always active and useful even if you have an answering machine. The Call Return (press 3) element of BT 1471 costs a fixed fee of 7.5p. The fee will apply when customers press "3" to return the call to the telephone number of the last caller and will be charged regardless of whether or not the call is connected. Dialling BT 1471 without using the Call Return will remain a free service.
If you don't want your number to be obtained through Caller Display or Call Return (1471), dial 141 before making your call.
1471 is FREE to use. However, calls returned from 1471 are charged at the normal rate and a fixed fee of 7.5p applies when customers press "3" to return the call.