Headlamp bucket question

[LizardsA]

I am struggling with fitting headlamp buckets to the headlamp crossbar on my 1928 RPU. The problem is that the "cups" on the crossbar that hold the headlamps are not tilted as they are on a 1930/31 headlamp crossbar. The result is that when fastening the headlamp buckets to the bar, the lamps end up pointing upwards with no adjustment available. I have attached a more detailed picture of what I am experiencing. And yes, I have tried turning the crossbar around in case it was mounted back-to-front, with no change in the problem.