Hi Darren!

There's has been an update. Unfortunately, the manual marking for the Short answer is not coming any time soon. But just to clarify something, as in my experience users often confuse Short answer widget and Post text widget which does offer manual marking. Short answer widget is intended for close-ended questions.  But if the question is open-ended, like basically writing a few sentences, let's even if you want the students to write only 50 words, you would want to use Post text widget. You can limit the character number of their reply to make sure they are short, but what's most important, you will be able to evaluate their responses manually.
I hope this makes sense, but please let me know if you have any further questions.