Even though the upstairs socket is "hard wired", it's still effectively an extension socket. With fibre, broadband is only available from the dedicated socket on the front of the new master socket that the chap will fit so it won't be present on any house extension sockets.
As far as I know, the "30mtr cable" you mentioned is an Ethernet cable that goes from the new router to your PC.
By all means, ask the chap for advice when he arrives to setup your broadband, but if he says he can only install a really long network cable then a HomePlug starter-kit like this one will enable you to get an Internet connection upstairs without any extra wires - providing of course that you've got a couple of free mains sockets. They don't always work effectively when plugged into power-strip extensions.