What I used to do is just bring in the boot door down to a near lock position and a mild press locks the door. Likewise if you seen the bonnet, the closing technique is a bit different. You just hold the bonnet 2-3 inches (somewhere I read it as 6-7 CM) up and leave, it will lock. That time too you will receive a bit banging sound. My wife also complains that I need to use a bit more pressure to close the door as she gets irritated because of the bang. I explain her that it is for safety and now she enjoys the ride on the co-passenger side with big smile as she feels safe riding in Punto. I am not telling that you are complaining but the reason why Fiat made the door bit heavy to close I explained. As I got used to this, sometimes when I go with my brother in law I apply a bit pressure on locking the door in his Polo, and I see a heavy bang noise . Then I learnt that the other vehicles don't need that pressure.