Betsy murders John, and packs his body into a steamer truck which is to be loaded onto a tramp steamer which will take "two, maybe three" months to be delivered to Australia. She's on a hiding to nothing. The powerful smell of a decomposing body will alert the crew of the steamer to its presence within days.
When Betsy throws an ornament at Jack, he asks that the next time she does that, she "tries to miss the Lowry", meaning the painting directly in the line of fire. However, the painting in question is clearly a modern abstract, and is not in the style of an L.S. Lowry painting. Indeed, none of the paintings that Jack owns seems to be in the style of Lowry.