Wing Commander CIC

I've played version 1 of the remake using a Demon, but having downloaded the entire version of 1.1 and restarted, I've got enough money to buy a Demon but I can't find one.

I remember completing the original game using a Centurion, but the 3rd Oxford mission in version 1 of the remake was impossibly difficult to do and so I did the whole game again with a Demon.

I have tried going to the usual places and checking the commodity exchanges, but no luck so far in New Detroit, Perry, New Constantinople etc.