(I thought I published this several days ago, but apparently I only saved a draft, so belatedly here it is)
Area D: two Rhodes Hearts (colour A, medium) either side of over lapping Cross Stitches (colour A, light). There is a little more stitching to do in this area, the chart suggests the lightest colour A should be used but I am considering another option. I will wait until some more stitching is completed so that I can see how the colour change affects the overall balance.
Area E: Upright crosses tie down the intersection of long stitches worked in a grid. The chart suggested the dark colour A perle cotton for these stitches. As I could not match this shade in perle cotton, I used Colour A floss in the darkest shade. The upright crosses are worked in alternating rows of colour A and colour B. The stitches also alternate between two shades of the appropriate colour. The chart suggested the dark and medium in each colour way, but I used the light and medium for colour A and the dark and medium for colour B. Finally cross stitches are worked into each 'diamond' shape formed by the grid using colour B light.
The central area is complete except for a few stitches in areas B and D.