As a matter of interest, before you started receiving these calls did you (by any chance) receive calls where no one spoke but you could hear a beeping sound, before a hang up?

Then when you did a 1471 all you heard was "you were called etc. but we do not have the caller's number"
I ask, as (quite often) these organisations use what's called a telecaster to call a number at random times of the day. when the phone is picked up, the software notes the time of day and whether a voice was detected. This then gives the caller a high probability of someone answering the call.
If you have/are experiencing the above type of call, then try this: When you answer the phone - listen and say hello once only, if nothing is heard, press the hash key (to the right of the 0) on your phone as fast as you can repeatedly. This will confuse the electronics (at the caller's end) and scramble the call making the timing information useless. If (however) someone (you know) is on the other end - you can always make up some "technically sounding" excuse.
I (quite often) used to get this type of call on my answerphone whereupon nothing was recorded except an automated voice saying "the other line has cleared". Give it a try, it costs nothing and may bring some peace of mind.
Please note, this information may have already been imparted (somewhere) within the forum before. If it has, then cest la vie and (kindly) ferme la bouche, as this type of information doesn't do any harm to be repeated (occasionally) for the good of all.
Good luck and Si thee