Routing Plan

We've tried to get Virgin Media to replace our incredibly slow previous WiFi provider for months, and finally we managed to get an installation booked. The brown box outside of our house has been installed and all that needs doing now is taking a cable from the brown box outside to our flat, this means drilling a hole in the wall and routing the cable above another flat to get the cable into our property, as the Virgin Media engineer told us.

In order to do this, we need permission from our landlord who has requested a "detailed and technical plan of the wire route, as this is usually what telecoms companies come to us directly with."

How would I get a technical plan of the wire route or is there any way to get a letter from Virgin Media explaining what work needs to be done to install the WiFi?

Thanks