Zanussi ZOB551X oven, low and high grill action

I have a perplexing situation here leading to a couple of simple questions but I’ll give as much detail as I can to at least show what I have done to get to this point.

I have a Zanussi ZOB551X oven unit. This has inner and outer grill elements with low and high settings on the control. The action as I understand it should be low setting – inner element only, high setting – both elements. Recently I noticed, (you can tell who does most of the cooking), that when the grill was on only the inner element heated up to glow red. I assumed the outer element had blown so I ordered a new one, (both elements are in a single unit).

When it arrived I duly isolated and opened up the oven to replace the elements and checked their resistances. Darn it, they were fine and virtually the same as the new one. Continuity connections from the elements back to the mains input seemed to switch as they should too. I was puzzled. I reconnected the oven and ran it up carefully. I had mains across both the elements when I should, inner on both settings and outer on high setting only.

According to Zanussi the grill should give low 1650W and high 2450W which makes the outer high only element 800W. The elements in the new unit measure 33R and 66R respectively and the old unit 32R and 63R, which correspond pretty much spot on to 1650W and 800W for 230V.

Now the crunch. This all seems to suggest that my oven is working perfectly and I’m a non-kitchenly talented individual who can’t tell when a grill is working or not! I had assumed that the outer grill should also heat up to glow red, even if slightly duller than the inner. So, is it really the case that the inner element is the only one to glow red hot, and the outer element is heating up correctly even though there is no visible sign of it?

And secondly a more general query found when measuring, is it possible that this unit switches the neutral and not the live to the grill elements?