Our street is on-road parking only. Last night I parked on the end of the row behind my neighbour's car. When I went out this morning someone had clearly reversed into my car, cracking the numberplate in two and leaving it dangling, with enough force to remove a chunk of it entirely, and leaving a dent in the grey plastic bumper. Neighbour's car was gone, leaving a large gap in front.
Have just had a look at their rear bumper tonight and there is a small crack and grey plastic smudge at about the right height - however, it's only a very small mark, and of course I didn't see it happen, so proves nothing really. It is entirely possible but unlikely that someone else parked there briefly this morning between both of us leaving. It's also possible that they didn't realise how much damage they'd done; their car is much larger than mine, maybe they had the radio on, didn't hear the impact.
DP is all for leaving the broken numberplate on their windscreen along with an invoice for the replacement plate. I despise passive aggressive notes, hate any confrontation re: cars and parking (so petty, have had parking issues before) and, of course, can't prove it was them.
However, if they are aware that they've caused the damage I don't want them to think they've gotten away with it, IYSWIM. How to proceed? Do I just let it go, for the cost of a replacement plate, and inwardly seethe? 