Just had a call from BT, they've detected a fault on the line (which is good because it means I'm not losing my marbles, and I don't have to buy a new router. It also means I'm not going to be charged for the escalation), and an engineer will be sent out. Now, I could have had one first thing on Monday, but alas, work commitments mean the earliest I'm able to be in for it is Wednesday. Still, at least a resolution is in sight.
In other news, Kill Bill Vol II tickets should be booked this evening, to go see it on Tuesday.