Sorry,
Hemi, I confess... I came across the Purdey cleaning case a few days ago, and was waiting for some unsuspecting shot-gunner to ask about a cleaning kit as an excuse to run it out. In reality, I'm like
hogdogs, and have separate rod/tip/brush kits for my rifle, handgun and shotgun calibers/gauges. You might start with a "full" kit for your 12-ga that includes solvent, oil, mop, and wipes in addition to the basic rod/tip/brushes. As you add more gauges/calibers to your collection, just get a rod/tip/brush kit for that gun. Brent's correct about a "universal" .22 rod being too flimsy for your 500.
If anyone is really interested in the Purdey kit,
Kevin's has it for just $5,473. If you're a cheap old phart, like me, you can get the Payne Gallwey chamber brush separately for £7.34 ($10.72) from
Attleborough's.