From past experience there doesn't seem to be any bottom line of quality for the engineers that come out for installs.
We've had both good (as well as a perfect install, the guy drilled several other holes I wanted in the walls for network cabling
) and bad (the guy managed to break the phone line 3 times while installing the TV - and yes I know they're nothing to do with each other
- all the while telling me he had no intention of turning up to the last 2 jobs on his list and it was TWs fault for overworking him).