I would install the cable myself first, and let the installers connect it up - if they are happy with it.
They will be pleased you have done half of their job for them.
As long as you it install it correctly, they shouldn't object - they just want to get home.
Make sure you are there on the day, in case there are any problems.
Do you need any additional cables put in for the charger?
Check first.
If you don't have the correct cable, you can always get the route ready, and help them on the day if really necessary.
I'm often present on jobs when communications people and suchlike are expected, as they won't run cables in lofts and under floors very often.
The more you get ready, the easier for the installers - so they will be more willing to go along with your plan.
They will be pleased you have done half of their job for them.
As long as you it install it correctly, they shouldn't object - they just want to get home.
Make sure you are there on the day, in case there are any problems.
Do you need any additional cables put in for the charger?
Check first.
If you don't have the correct cable, you can always get the route ready, and help them on the day if really necessary.
I'm often present on jobs when communications people and suchlike are expected, as they won't run cables in lofts and under floors very often.
The more you get ready, the easier for the installers - so they will be more willing to go along with your plan.

