Why should that be China's problem?

Someone imported it, someone's selling it in the stores.

If the price of the "disposable" is, say, £5, make the deposit £50. Suddenly all the vapes will end up back at the retailer.

And make sure retailer has the financial incentive to return the used disposables and that's it.

I'm confident the lawmakers have been bribed to refuse to tackle the problem, otherwise how you can explain minimum price on plastic bags but tolerating toxic landfill fires and staggering waste of lithium (recycling will inevitably br fixed soon).