It's called "contestable work"
When I was getting the quote for a new supply to my house, one if the things in the quote was dig a connection pit in the grass verge on the other side of the road. The quote was something like £2K and that was already with me digging the trench on my own land.
As it worked out, I got the water connection first so Scottish Water made the road crossing. While that was open I dropped in a length of duct for the electricity, and then dug my own connection pit the other side of the road. So all SSE had to do was pull a cable through the duct into the meter box and make the connection in the pit I had dug. That saved almost £1K from the connection cost.