" gurgled happily, sounding much like they
were saying:

Are there any wiring bodges?

A common wiring problem is the red (power) and yellow (standby power)

ITYM "Memory" and "Ignition live"

wires shorting together, deliberately joined or transposed.

Joined isn't a problem - you'll just have a head unit that can be used
with the ignition off.
Shorting together'd just get you a head unit that might sometimes stay on
or come on when the ignition's off.
Transposed will just give you a head unit that can be switched on when
the ignition's off, but only keeps the memory when the ignition's on...

(Assuming, of course, there's no way for the ignition live to feed back
into the rest of the car's electrics.)