Malone, following the instruction gives two crossing chains of diamonds, i.e. the cells that are not made 39, whereas the thematic object should consist of two bands. The only way of doing that would be for the unaffected areas to extend beyond the cell boundaries, which would breach the preamble.
Re the alleged dumbing down of the Listener in earlier comments, the average level of difficulty so far this year has been about the same as most other years. Last year was a tough year but it wasn't typical. I remember complaints about dumbing down in 2007, which was a particularly easy year because there were few really challenging puzzles. This year I think there have been around ten puzzles that were above average difficulty , and one, the most recent numerical, that was at the top of the scale (for some it was off the scale).