I have heard that onions and quaker oats that are sold in cans from England (i.e. onions and canned Quick Oats by ’Mornflake’ with the Hashgacha of the Rabbanut of Manchester, England) requiire checking for bugs, etc... Is this true?

Without wishing to refer to your specific query - I can tell you that everything with a Hashgacha at the time of its manufacture may become insected after its manufacture. esw