no ignition lights, no crank /no go!

i have a 306 srdt 1.9 (1.9 turbo diesel) sedan. I turn the key and
there are no ignition lights
come on, and further turning it doesn’t make it crank over or
anything. Can’t even hear a click
on the starter motor solenoid. The battery is fine, as we tested it
with a multimeter and
tried a different battery. no in car fueses have blown neither the
one’s under the bonnet.

my friend came over and took the steering column casing off and used a
peice of wire and managed
to apparantly hot wire the car. it worked , ignition lights came on
and then used the key to start
it. he then thought it would be the ignition barrel at fault. so off
my other 306 we swapped it
over and did not fix it. he then saw that a previous owner had run a
wire from the starter motor
solenoid to the ignition and somehow drawn power from near the heater.
he thought they had done
this bodge to bypas a problem and that he now thought their bodge has
stopped working. he ripped
their bodge off and now intends to find the initial problem. i was
just wondering if anyone had
any suggestions or they have had a similar problem? ps the earth on
the car seems fine. until
he looks further he thought that it looked like the red and white wire
(brown connector block)
in the steering column leads into the car into some kind of fault, but
was unsure where it went.
he may be wrong. any electricial masters out there?

PS i do remember before this happened, the thermostat guage went loopy
(just kept going from
side to side) - coolant was fine - maybe a sign of something
electrical failing?

i appreciate any comments