Being the UK someone will scam this and make their own fake bottles to claim back more money.
Also would the extra energy consumption be worth the extra plastic collection? Just because it ticks some boxes doesn't mean the results will be better for the environment. 1,000's of machines being on, extra collections. Cash handling(unless they will be card only) all has an impact.
I suppose the collections could be resolved by forcing goods suppliers to handle them on drop off of the store's goods. Let's say a firm makes a delivery to Corner Shop A, now they have to collect the bottles at the same time and return them to base.