You need

\setupsectionblock[bodypart][page=yes]
\setupsectionblock[backpart][page=yes,before={\page[left]}]

I tried that Wolfgang.

However I'd like the pages setup like in my last example with, in a double sided document, the back page on the [(next even page) + 2]. So, refering to the output of the last example: page 10 being a blank page without page number and, as is, the back page on page 10 + 2 = page 12.

Alan