From my experiences,they are a bunch of lazy bastards.
It seems to be that going over roofs/under floors/into ceiling voids is classed as an extra payment and they quite simply refuse to do anything that would resemble neat.
As a sparkie, I wouldn't dream of clipping along skirtings etc unless it was absolutely necessary.
When my folks got theirs in,the guy was gonna have a phone cable clipped round near enough the entire ground floor to get to the box.
I went under the floor myself and done it.
Useless,lazy bastards.
No offence to any installers here,but if that is anyone,learn to do your job neatly please.