I'm in a similar situation to you. A cabinet in my (Potterspury) was 'finished' last week, ahead of when it was added to the updated list on the Superfast Northampton blog.
The blog states that there are 2 cabinets in the roll out for my exchange (Yardley Gobion). I did a little recon on Friday after work and noted that that exchange serves 5 cabinets (at least), 3 in Yardley Gobion and 2 in Potterspury. My cabinet, number 4, is the furthest away and non of the other cabinets have a shiny new FTTC DSLAM's stuck next to them. Checking roadworks.org, it shows that cabinet 2 has plans for an upgrade in July. So it would seem (I hope) that only cabinets 4 and 2 will be fibre enabled. Bear in mind that my exchange serves 1145 residences and a handful of businesses. The DSLAM installed in Potterspury is a '288' I believe!
And to thicken the plot further, as far as I know, Yardley Gobion isn't fibre enabled yet.
It would be good for everyone if BDUK published details included expected timescales. I'm sure that would stop a lot of wasted energy and hope on the part of the consumer.
ISP: Coms.... Soon to be Xilo
Service: Coms Complete DSL100
Router: Billion BiPac 7800N
Attenuation:38.5dB - 40dB
SNRM: 3.4dB (manually set)
Current sync: 9786kbps