Would anyone on the list happen to know the best place to pick up a live feed from the loom when the ignition key is removed and non live when the ignition is running. This is to enable me to fit a LED as a deterrent to indicate that the car has some form of imobiliser as the factory fitted one has no indicator etc. (1/00)

There is no such wire. If you want to make the led go on when the key is removed connect it like this:
positive from the led to battery (such a wire is called +30 in car terms)
negative from the led to ignition (such a wire is called +15 in car terms)

So, when the key is in, the led has 12v on both wires and won't light up. When the key is removed, the ignition will be cut, but since there's a lot of stuff 'hanging' on that wire, the few mA that the led consumes, will find their way through the system. The led will light up. An easy spot for these 2 wires is the radio. It both has a +30 (for memory) and a +15 (acc position) wire. PS, make sure you get a 12V led! (1/00)
Are you sure it has such a thing? Why not use a small relay running from switch live to disable the LED? A quid's worth and relay and two connections, one to switched live and one to permanent live, is probably easier. But maybe someone will come along and report there is such a live available! (1/00)