I'm only sort-of aware of the background on this one, so bear with me:
Avon is a brand of cosmetics being sold door-to-door, so it became a favorite of many transvestites in the UK, many becoming Avon salespeople themselves.
So "Yer da sells Avon" could also be meant to imply "your dad is a transvestite".
Avon is a brand of cosmetics being sold door-to-door, so it became a favorite of many transvestites in the UK, many becoming Avon salespeople themselves.
So "Yer da sells Avon" could also be meant to imply "your dad is a transvestite".