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Yes - they were the radii, but I see from your new pictures that you cant increase the "bottom" Radius. I believe though that you have plenty of room to make the "thickness" over the lock greater - if you were to do this - ie make the hollow over the lock deeper, this would strengthen the lock section and reduce the likelyhood of it splitting. As shown in Green below - either that or make the total depth equal to the depth from the "bulge" to the door.
It would also be possible to increase the size of the cover as shown in the other pic in green - A rib would have to be moulded in to replace the old edge though. - and higher material costs.