Kitting out 12 exchanges - is short hand for the man hours spent getting fibre tubing into the ducts in the area, and then blowing the fibres through etc
There is a fair bit of work that goes on for FTTP roll-out, a fair bit more than FTTC.
In terms of the exchange itself if it already has FTTC then the kitting out there is done, but if FTTP arrives first then that has to be done too.
Delays are mainly down to it taking longer to get the cables in the ducting etc. http://www.farina1.com/fibre
shows a fair bit of the kit, including how fine the actual fibres themselves are.