Your recordings do sound like a HR joint (as I have one under investigation by BT at the moment) but because you are near that transmitter it is acting like a old type of 'Cats Whisker' crystal radio set and picking up that strong signal.
I have a iphone and that has a 'Voice memo' app that I have recorded some of the crackles of the bad joint on a QLT.
If you do a QLT 17070 / 2 and after she says goodbye, wait for the tone, wait until it finishes, then after the tone you can get a period of the line without her saying QL test every 30 sec.