That does look interesting, nice find.
The vents would be part of the stereo surround usually.
You could try ebay with the worldwide search or other places but the vents I have not seen before.
Maybe one of the members with a march version micra could kindly post what they view for the air vent this could be helpful or just search for them.
Here is one I just found that is different to what I have seen so far.
