Account Colour Clarity

I have 6 accounts in K9 mail. On the old version they all had clear, different colours so I could easily see at a glance which mail was for which account in the unified inbox. With this version 5.800 the clear marker has gone so the clarity is lost, just a tiny mark next to an email that is lost in the preview lines. Also the colour palette is reduced so I had a (bright) yellow and (medium) orange account before. Now the orange and yellow are almost indistinguishable when viewed side by side in the unified inbox.

Please give me back the full height indicator and the full colour palette, or at least a more usable palette even if it isn’t infinitely customisable.