Hi Adam
can you post a better photo that clearly shows where the break is?
I'm assuming the break is in the pivoting arm, I'd guess it is common to other Hitachi models and it might be the same as other brands. I think early Hoover Premier was based on a Hitachi design but no guarantees about that.
I'd be scrounging for a dead similar machine (Check gumtree and select "price type - free".)
Otherwise maybe try to repair the broken bit with epoxy putty such as Selleys Knead-It.
I'll keep an eye out when scrounging...