There is obviously no connection via the wall sockets. As this wiring is your responsibility, you will be charged £130 for the Openreach visit.
Do you know if you have FTTP (Fibre to the Property) or FTTC (Fibre to the Cabinet)?
If you have FTTP (Fibre to the Property) your Smarthub can not be connected to the telephone sockets in the property. It must be connected to the fibre modem.
Yes or else you need to run an Ethernet cable to where ever you want the Smarthub to be sited.
You will need a couple of BT Mini connectors, which are available from BT at a discount if you have BT Youview.
Mini connectors link the home hub to the YouView box using the mains wiring.
See this post https://community.bt.com/t5/YouView-from-BT/How-to-connect-YouView-Box-when-hub-in-another-room/m-p/...
If everything works when the Smarthub is connected up in the cupboard ie the way correct way, there is nothing that the engineer will do because there is no fault.
It is up to you to sort out your internal wiring and how/where you want the Smarthub sited.
If you don't want to run Ethernet cable you could consider using powerline adaptors. You plug the master one in to an electrical socket near to the Smarthub and connect the Smarthub to the powerline adaptor by Ethernet cable. You then plug the slave powerline adaptor in to an electrical socket near to your TV and connect your TV to it by Ethernet cable.
This shows how it would be done using a PC but it would be exactly the same with your TV.
One thing to point out, if you have a UHD youview box and you probably have given you have FTTP, is that power line adapters won't work for a UHD stream. You will need a hard wired ethernet cable from your smart hub to your Youview box.