I lived in Montevideo for about 4 years 1958-1962, I was 2-6 years old and loved the cars there, Metropolitan, BMW 601, 2CV. I am in contact with Jorge Schneckenberger in Montevideo who is in the Heinkel/Trojan club, he is very into cars, he may be a useful contact for you. We lived just off La Rambla, I think near Punta del Este. Nearby was a large hotel, a French Lycee International (school) and an ice cream parlour. Our house was at the corner of a road junction, with a huge honeysuckle bush around it. We walked along past our bush, crossed the road, went one more block then crossed the Rambla to get on the beach, the hotel and ice cream parlour were to our right as we walked to the sand. I would LOVE to go there again sometime!
Jorge has found several Heinkels surviving in Argentina and Uruguay, and does some restoration. I think he is interested in other cars too.