Sabotaging his TV by removing the fuse from the plug? (She gave it the TV chap before he left.)
I presume Mr Lloyd was fine with his old TV and so it was her idea to get a bigger screen... though he seemed pleasantly surprised at the quality of the picture so I suppose that bit ended up being a favour for him after all.
But asking for £450 when it cost her £150 is shady. And paying the chap in cash is a bit shady as well (tax evasion?). (I wonder where the TV came from? "Fell off the back of a lorry", as they say here in Germany? Maybe in a pizza box?)
Plus the way she looked over his shoulder made me wonder whether she was trying to memorise his signature....
On the other hand, the van pulling around the corner led me to Mr Lloyd's house!
I believe the "2 Llygad yr Haul" is on Lon Bulkeley at https://map.what3words.com/youthful.exhale.stiffly ; have a look at the Google Street View.