Kind of despairing... Our lovely, friendly staffy has chewed through all of the Kong Extreme toy shapes. At first, it took days, but in the last two days he has chewed through £30 quids worth of the XL Extreme Kongs within minutes as getting even better at it - aaaahh! (And then starts to eat them, so they have to be removed straightaway). Are there any really, GENUINELY INDESTRUCTIBLE dog toys? I know there's bones, antlers etc. (and raw bones in particular were recommended to us for not splintering), but after really a plastic-y type one that will be longlasting and slightly softer on the teeth as he's an older dog. Thanks!