I exchanged some emails with Elektra and can't say I'm thrilled with the response.
After sending the photographs showing the difference, and asking when the design changed, this is the answer I got:
the two parts are the same. You can fix the heating element in your coffee machine.
I don't think I am going to get a response to my second email (of three) pointing out that a difference in size makes the elements different. It looks like Elektra does not sell an element that fits without blacksmithing. Sadly, no-one seems to know when the design changed (I assume that elements that fitted were once available).