Thanks for the support, Duskheaven. I really wanted to give the automatic marking away for free. It would help a lot of students. It's just really hard to fund it especially if people abuse it.
However, you've given me a lot to think about. Thanks Duskheaven.
Personally, long term I believe it will have to become free (for students) at some point within the next 5-10yrs or so because if you don't release it for free, someone else will IMO. UNLESS, you can truely make it better than every other service - greatly expanding the scope of this project (for example, pointing out errors in initital response word by word, analysis of the text and why, tips etc, user friendly interface, perhaps other intergrated services etc).
Perhaps, the easiest way to commercalise it is that marking is free, but you can see band 6 response for a fee. (I would greatly prefer both services be free, as free tools like this reduce educational inequality, but that is just my capitalist mind working). OR perhaps an analysis of where the written answer is wrong is for a fee.
There should be some way to prevent doxxing.