My workaround nowadays is to go to the Network Manager icon and edit the connection to put my desired MAC address as the 'cloned address'. 
When i start the computer back up, it's once again got a different MAC address and eth* number but i can change it to the current one - which is a tiny bit faster than typing console commands but still not a fix.

The relevant content of /etc/udev/rules.d/70-persistent-net.rules shows:

# PCI device 0x1969:0x1026 (ATL1E)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:00:51:81:06:f3", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth0"

# PCI device 0x1969:0x1026 (ATL1E)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:00:c0:1f:39:f3", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth1"

# PCI device 0x1969:0x1026 (ATL1E)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:00:53:52:6a:f2", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth2"

# PCI device 0x1969:0x1026 (ATL1E)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:00:30:42:91:f3", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth3"

# PCI device 0x1969:0x1026 (ATL1E)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:00:37:3c:c9:f2", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth4"

# PCI device 0x1969:0x1026 (ATL1E)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:00:8c:0b:a6:f3", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth5"

# PCI device 0x1969:0x1026 (ATL1E)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:00:4a:73:92:f3", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth6"

# PCI device 0x1969:0x1026 (ATL1E)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:00:e9:61:8b:f3", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth7"

# PCI device 0x1969:0x1026 (ATL1E)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:00:70:69:3d:f3", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth8"

# PCI device 0x1969:0x1026 (ATL1E)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:00:32:ff:77:fa", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth9"

# PCI device 0x1969:0x1026 (ATL1E)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:00:c7:1c:0c:f5", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth10"

# USB device 0x148f:0x2870 (usb)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="80:1f:02:06:1f:11", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="wlan*", NAME="wlan1"

# PCI device 0x1969:0x1026 (ATL1E)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:00:5f:5f:a4:f3", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth11"

# PCI device 0x1969:0x1026 (ATL1E)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:00:fc:d3:bc:f2", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth12"

# PCI device 0x1969:0x1026 (ATL1E)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:00:fc:4d:b7:f3", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth13"

Why does it keep getting a new address, hence a new eth number assigned?  

Is this a driver fault or a bug in an ubuntu config file? And more importantly, is there a way to fix this? :(