Nice work.
A couple of thoughts.
The first photo of the red clio, it needs a bit of space around it, it looks too tight too me.
All three shots of the Mk5 Golf have a bit too much foreground, which particularly as the foreground is dark makes the whole photo dark. It looks like you've given space for a load of writing as if it was for a marketing campaign.
The angle of the Fiesta is a bit too far, I don't mind angled shots but it looks sea sick. Rotate it round counter clockwise a bit and crop it to reduce the amount of black background.
Having so much dark background in the image detracts from the real focus of the image.
Finally, the large logo on some of the photos detracts from the image itself.
But I'm being picky, they are good shots. Good lighting (the key to good photography), composition, colour and sharpness.