It really annoys me when I see damage such as this - totally pointless and really annoying, to put it mildly. Does the train station car park have CCTV coverage that you could ask to view to see if the perpetrator can be clearly seen? If so, then it might help the police to trace them if you decide to report the incident to them.
It looks as if it’s the trim on the front door(s) that’s been damaged. Assuming yes, the gloss black B pillar trim looks to be no.35 on the diagram at the link below. There are different versions, but I’m assuming it’s the ‘trim with lettering’ version (with ‘Volkswagen’ at the base of the trim panel) that you’d need. There are a range of part numbers for that specific item of trim, so it’d be best to check with your local VW parts department to make sure you get the correct part for your year and model of car.
The rubber looks to be no.6 on the same diagram - described as ‘window guide’. Again, there appear to be a range of part no’s. for this part, so again best to check with your local VW parts department to make sure you get the correct part for your year and model of car.
https://www.lllparts.co.uk/catalogs/vw/ ... 837/837060
Sorry, I don’t know how easy it would be to change the trim or rubber, or if any special tools would be required. It might be worth doing a search on YouTube to see if there are any ‘how to’ videos. The Golf has the same type of trims so if there aren’t any videos of these trims being removed / refitted on the Polo, there maybe some for the Golf. If it’s not a straightforward job to do then it’d be worth asking the VW dealer what they would charge to do the job, and also ask a few independent body shops in your area what they would charge.
Good luck, I hope you get it sorted without too much hassle.