According to this[1] you'd have ordinary workers earning 22 shillings p/w (£57.2p/y) and highest skilled labourers (firemen) sometimes earning £300, but yes the average wage seemed to be around 150[2]. (I think most people googling the average 1920s wage are getting the Australian-Victoria data accidentally, which is a bit higher, but it's still in the same ballpark) I think the Christie's equivalent today to US household income would then be 67000*700/150 = 313,000
[1] https://api.parliament.uk/historic-hansard/written-answers/1... [2]https://ourworldindata.org/grapher/nominal-wages-consumer-pr...