I want BT infinity but....

Question

I am after some guidance about the installation.  I understand the basics about the need for the Infinity modem to be connected to the master socket and the special data cable between it and the home hub but....
Here is the layout:
I have the BT line entering the house via a junction box adjacent to the front door.  From this point it is cabled to the master some 3.5m (probably 8m cable run up and down the walls) into the hall and this cabling is fully hidden as it was installed during the house build.  From the external junction box there is a 22m extension run around the side of the house to a rear bedroom / office where I have the ADSL modem / router presently installed.  The router serves both a WiFi network and cabled Ethernet in the house, hence it is difficult to move.  As things stand it would appear I need the Infinity modem in the hall connected to the Master with the data cable run around floors and doors upstairs to where the present router would be replaced by the home hub.  Frankly this would be a deal breaker as I do not want ugly cabling running around the house.  The layout is complex - please take my word it is not going to happen (whilst Mrs Blink lives and breathes!).  So my question is whether the master location can be moved from the present position to the upstairs extension?  I appreciate it would not be the closest point to the junction box, hence not the closest point to the termination between fibre optic and copper so the speed may suffer a little.  I have been quoted 26Mb but since I presently have 3Mb I suspect I will still be significantly better off.
and a second question - I assume I am correct in thinking that I can actually use any router with this?  The home hub looks okay but appears not to be wall mountable.  No big deal either way but just interested.
Thanks in advance for any (constructive!) replies to my first post.  Yes I did search but failed to find anything
Cheers
JB

Answer 1

Thanks for this, however I do not quite understand how you can do away with the junction box since the cable coming into the property is spliced at that point.  To try to be more descriptive, imagine a letter "T": four wires come in from the bottom (2 for each line) and are split left and right.  To the right, two wires (line 2) are terminated in the junction box and the other two join to the house wiring (ie the phone cable installed when the house was built) running to the master for line 1.  To the left, 4 wires (ie both lines) run round the outside of the house and up to the office.  There line 1 is terminated in a std socket and line 2 is terminated in the master.  So regardless of which of the line 1 positions is used as the master it will be directly connected to the incoming line.  So the question is now (and apologies if I am being incredibly dense here) are you suggesting that in a "T" shape layout as I have with a socket on each end of the horizontal line, if the "T" is not symmetrical, so the vertical line is not in the middle, the master must be connected to the shorter of the horzontal arms?  If that is the case then line 1 will have to run back down the house again to the junction box before going into the house to the old master position.  I am not sure whether there are spare cores in the cable used. 
thanks for your patience!