Caravan boot door coming away from hinge

The front caravan boot door is coming away from long piano hinge.it happened before whereby the door fell off
Took it to a jayco recommended repairer who stuffed the Jiob and the door fell off while we were standing there plus they added extra unneeded holes. My husband and a friend managed to get it back on themselves but it pulling away again and will soon fall off. out of warrantyt too. Anybody experience this and if so how did you fix it? A caravan repairer has suggested rivets rather than nails. will prob need new door but need suggestions on how best to get it done properly.
Linda