I damaged a parked car and left my details but have not had any contact - do I need to inform my insurer?

I accidentally scraped up against a parked car while attempting to park. There were only a few very minor scratches on the car and my car was left with a few scuff marks. I waited for 30 mins and the driver...

I nudged another car and left my details but have had no contact - do I need to inform my insurance?

In a very tight road with vehicles parked on both side, I tried to pull in to allow a car to pass and misjudged the space and nudged the other car's bumper leaving a mark on my car and a mark on the other...