Cool! but that is not quite what I meant.
As a victim of washboard/tire carrier mishaps, I've actually seen what NWOODS is suggesting. My Jeep suffered a smashed rear light and big time corner damage when the deflection that occured exceeded the catch mechanism . . . . that said I did have a larger tire (more weight) mounted than the LR3 OE size.
BTW, my tire did not exceed the weight limit of the carrier . . . . . even with two contact points, the carrier moved enough (mostly front to back movement) to instigate an instant pooper pucker. It was funny afterwards and my buddies got a good laugh.
I think your design is nice and clean, I like it . . . . .you'll have to see how your prototype survives the vertical and lateral (pitch and yaw) deflection . . . . your greatest stress point with the current design is going to be where you mount it to the bumper (no big surprise) . . . . .your moment of enertia is going to occur high where the tire/wheel mounts (again, no big surpirse). . . . .it's gonna bounce, hard to predict how much because it's not very long/tall.
It's obvious in the pix that your hinge is robust (plenty of material, grade 8 hardware) . . . . you may want to consider a backing plate to help reinforce the stamped steel bumper.
Well done, let us know how the prototype turns out mounted and wheeled.