Photo very apt
Wiring diagrams (at least similar) can be found at :
http://www.minimania.com/MM/Mini_Wiring_Diagrams_Now_On_Line_1362.htm
eg check out the 850 one :
http://www.minimania.com/images/wiring/PDFs/wiring15.pdf
There is a basic colour coding set of rules (valid for all older minis) :
BROWN comes from starter solenoid /Alternator/Generator and brings in the power to "Terminal 1" = Unfused always live.
The other side (via fuse) Terminal 2 = Fused always live - and
PURPLE wires.
Terminal 3 = Unfused via Ignition Switch = Unfused switched - WHITE wires
Terminal 4 = Fused via Ignition switch = Fused Switched =
GREEN wires.
------ 1 <-> 2
--------
------- 3 <-> 4
-------