Thanks Hoot, that quote was from The Royal Collection trust.

https://www.rct.uk/collection/913692/rag-fair

Doesn't mean they were right by the way.

Meanwhile your ancestors sound very interesting. Do you have any family stories. Are you familiar with the area? I used to work near Tower bridge in another life 50 years ago. I can't remember tripe sellers, but there was Mossy and his wife who sold enormous boiled ham sandwiches wrapped up in newspaper, just over the bridge. They would be closed down immediately by the health and safety today.