I doubt many Brits have ever eaten boiled beef I certainly never have.
Do you lead a sheltered life perhaps? Maybe boiled beef is just a Cockney thing, I wouldn't know about that but here is a link to a page with a recipe for "Boiled Beef and Carrots" with this comment added: "Immortalized by the old music hall song, this is a truly traditional Cockney dish."
http://www.britannia.com/cooking/recipes/boiledbeef.html
Over the years I have come to associate boiled beef, maybe not as a mainstay of British cuisine, but certainly not all that unfamiliar. Admittedly the evidence was hearsay in nature and not subject to personal verification since I have never had the opportunity to visit your "Blessed Isles". If I erred, I apologize for my ignorance.
Regards,
GtG