Your first link says the exact opposite of your claim. It says it's legal to store above 30L and below 275L of petrol if you inform the local Petroleum Enforcement Authority.

Even above 275L, it says you need a license - it doesn't say it's illegal.

Fuel does go off, but if you have reason to store it, you probably have a use for it, so as long as you cycle the fuel, you can store an emergency supply indefinitely.