Yes. There will be minor deviations from the values as the element is probably a coil with some inductance although in practice that is normally discounted.
Sorry to be particular, but in all of the above results you come out with a load of greater than 32amp. It seems that there's a general view that that'll be OK because you've put plenty of 8.5kW showers on 32 amp mcb's over the years and never had any problems at all. A teenage girl in a shower will strain the close margin installation, leaving a soapy person with no shower. My college drilled into us the mantra Ib ≤ In ≤ Iz and, in a 2391 exam, if you even suggested that it was OK to have Ib > In you'd quite rightly fail. Those bu66ers at C&G deliberately set the questions to have you sit on a fine margin and make a mistake. Sorry, it ain't right. 8.5KW is too big for a 32A MCB.
Out of interest, does an MCB operate directly in relation to the current, or is it also affected by voltage?
I once had to drag a fainted woman out of my shower to stop her from drowning. I never got my soap back.