The Disklok finally arrived this morning, and on first inspection it looked pretty much identical to my old Disklok (which I bought circa 2002), but after closer inspection it's interesting to see the subtle differences between the two and where they have changed things presumably for security/weakness improvement.
I won't list the changes on here (for obvious reasons), but the biggest difference is the new one closes/locks on the smallest gap 3, where as the old one closed/locked on gap 2, this means the new one is snugger and some of the natural openings are also covered up.
If you have an old Disklok, then this is seemingly worth the upgrade.