"Bought it", yes, that's familiar, especially for death in military combat.

But "Bought The Farm" - I think that is very much a North American idiom, and one that hasn't travelled, unlike a lot of North Anmerican idioms hasn't ever been exported. We see enough American filsm and TV, but I can't reecall ever coming across it before these threads.

It didn't even crop up in the Dead Parrot Sketch, which covered the territory pretty well.
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Gone to glory Turned up his toes