Simpler recycling : https://www.gov.uk/government/news/simpler-household-recycling-rules-come-into-force-across-england - but that specifically covers the number of containers that are allowed to be used and what should go in them.
For food recycling the rules are :
So @trousers - plastic bags are not allowed, unless they are compostable
The only real restriction is on oil and liquids, but small amounts of oil - i.e. what's left from cooking roast potatoes or fried eggs - can be poured in and soaked up by what's in the bin. But surely people already have a way to dispose of this rather than pouring down the sink and blocking their own drains?