I waited for one that Plusnet had arranged, sat with clear view of the front door. Just as well..
I saw the van pull up. I saw him get out. He came bounding up, never knocked, slipped a "Sorry I missed you" card through the door - carefully - and was on his way back to his van when I ran out and collared him...
All because my wiring needed to be checked. Apparently, my wires know the difference between daytime and nighttime, and that's why it's slower in the evening... Plusnet said "not contention", I of course had to wait in.
So he got to work, everything fine. I explained it was obviously contention but plusnet assured me it wasn't. He the phoned his BT helpdesk and they said "yup, hot virtual path" and switched me to another. Problem solved. So, a good result - but was still unimpressed at the "missed you" bit. If I hadn't been watching at that minute, I'd have wasted the day.