2000Z3M Roadster Tire replacement

[quiet330]

I had new replacement tires installed on my Z3 and the shop had to cut the sidewalls on the rear tires in order to remove them. Then they had an extreme amount of trouble putting the new tires on the rear rims - severely scratching one rim. Their explanation was that because of the low profile and deep dish of the rim the machine could not break the bead. Is there anything special about changing the tires on these rims or did the installers just not know what they were doing? I went to a major discount tire dealer. Is there any way to tell if they damaged the bead of tires without having someone take them off again?