When I worked from home once before, I had a line put in and the master was on the wall of the upstairs bedroom I was working from.

Though it's not what you want hear, the chances of getting the second line from Crowthorne are slime to sod-all. I was at a house that was fed off Eversley, and there was still an old defunct ISDN line from the previous owners which I proved still went back to a cabinet served by Crowthorne ... the punter tried, in vain, for several months to get a service from there, but every time she ordered, the CP said no. The ISDN had originally been built from Eversley, but due to line length, wouldn't work, so the engineers were able to reroute it, there being a pole served by Crowthorne just up the road. The punter didn't mind the number change, and all was well. (Things like this could be done in the 'old days' of BT ) Out of interest where are you in Finchampstead, exactly ?