Network addressing

Hello
I’ve flashed the eMMc with Angstrom but have booted off the SD card running Debian. I keep getting assigned the DHCP address of .23 instead of the static address of .15 that I’ve assigned in /etc/network/interfaces. What am I missing?

auto lo
auto eth0
iface eth0 inet static
address 192.168.1.15
gateway 192.168.1.1
netmask 255.255.255.0
network 192.168.1.0
broadcast 192.168.1.255

I’ve reloaded and rebooted the BBB, but to no avail.
Thanks for you help.

Is it running Network Manager? If so a lot of the setup is in
/etc/NetworkManager/system-connections.