I say "just", in my case that would be a fairly big task.
What makes the national job hard isn't that a few properties have a big task, but instead the sheer number of properties to deal with individually.
To be honest, I don't really understand how it works practically..... if you already have FTTC, as most people do, do they just need to run fibre from your local cabinet to your house?
It is slightly more complex than running fibre from the cabinet, but that's near enough for this discussion...
What has happened to the median line, so far, is that the first 3km of copper has been replaced with fibre, leaving the last 350m still as copper. Stated like that, it appears that BT have done 90% of the work, right?
However, the fibre in place is shared by 300 customers. To get fibre to the premises, you only have one tenth of the total distance left to go, but you have to repeat that 300x. Combine the two, and (at its most simplistic), you have 30x as much work still to be done.
An analogy: picture an oak tree. You need to run fibre from the base to each and every leaf. As you trace the path to any one leaf, the trunk covers half the distance. The 10biggest boughs cover the next 40%. The remainder is a short distance along piddlingly-insignificant and thin branches. Short distances, but there are thousands of them.
In reality, the distance left to go with fibre is like the tree - there are still shared branches to go, so it isn't really 300x the effort, more like 5x. However, you only get that gain if you convert whole branches at a time: every house on an estate, for example. FTTPoD is closer to a "one leaf at a time" strategy that would be maddeningly expensive.
Aside: Why isn't it a case of running fibre to the cabinet?
The cross-connection point in the copper world is the PCP. In the fibre world, the equivalent structure that holds fibre splices is the aggregation node. This site underground, and is the point that new FTTPoD or FTTP fibre has to run back to.
So the fibre would run back to the cabinet only if the cabinet had an aggregation node. However, there are probably 2-5 cabinets per agg node.