Ah, I've learned something. This whole time I thought that ID19 was just the code for the Citroen DS, I didn't realise that the ID19 was a lower spec model which was released later!
So there is a DS19 and an ID19. Interesting!
So it doesn't have the all-in-one suspension/braking/steering/clutching hydraulic system then?
Does it have the headlights which turn with the steering rack?
It has the suspension and the headlights. It doesn't have the semi-auto gearbox or the one-finger PAS.
So originally there was the DS19. The ID19 was introduced as a cheaper model below it after a couple of years. As engines gained in power and size those numbers went up - DS20, DS21, DS23. The IDs went to ID20 before the model was rebranded as the D Spécial and the D Super. Later there was a D Super 5 which had the DS21 engine and a 5 speed 'box.
Having test-driven a D Super 5 I'm not sure I particularly rate the later gearbox. Just seems like cramming the extra cog in didn't do a great deal for the quality of the gearshift compared with ours. And it's not as if it made the car much more long-legged.