Tom andy That's fair. This issue might apply to other levels too as both the order and orientation of blocks makes a difference to the simulator (I saw this on one level when rotating a yellow rectangle through 180 degrees).
ColonelFazackerley Faster and fewer blocks. I got this on my 3rd go. You could just call me lucky, but I think this one does not earn the extreme flag. I really like @andy's last solution.