As a radio Ham I got blamed for every blip and glitch, I have had 2 more sets of complaints from neighbours and the first thing I do is ask for dates and times to compare with my log book (no longer a legal requirement), they then come back a few days later with a list.Going back "a bit" I had a friend who was a radio amateur, and lived in a terrace. Similar to the above, his neighbour had TVI problems - each time he came banging on my friend's door he'd direct him to the Post Office to fill in a complaint form.
This went on for a bit, and eventually my friend got fed up and filled in a form on the neighbour's behalf. The neighbour was much more uoset then - he didn't have a TV licence !
As a postscript, my friend was in the post office about a week later - and the lasy behild the counter casually mentioned that she'd sold a dozen TV licences in his street that week.
One list was obviously not my fault as it was right through the day, that turned out to be a local taxi company and I traced that to a rotted join in the aerial cable... and fixed it for them.
Other was continuous for several periods of 10 minutes every evening, that one was easy to identify, all I had to do was look for the purple lit window.
I did get to know the interference group very well and did spend some duties with them on, let's call it, unofficial training.
Part of my duties while working for BT was on loan to the TV detector vans, my job was to drive a van around housing estates very slowly, that was the van with blacked out windows so nobody was able to see how empty it was
The queue in the post offices the following day was comical, another job that went with the duty involved a camera and a queue.
