Oh yes, there are a lot of terrible installers. The guy who installed ours was fine with changing the LNB on the dish but didn't have a clue what he was doing when it came to the Q box itself. I had to show him how to connect it up!When we got Sky Q, the installer stayed until it showed as he'd said it sometime has issues. Didn't take long and off he went, all fine.
Sounds like some installers are better than others.
The current issue is with Sky's activation servers - it's not connecting properly with viewing cards, therefore leading to many, many disgruntled posts on the Sky Community forums over the past few weeks.