Here is the workflow I came up with. You will need a Google Apps account, and an iPad with Google Drive, Goodreader (make sure it is linked to your Google Drive account) and Recordium installed on it:
1 - Open Recordium and record audio feedback for your first student.
5 - Meanwhile, go back to Recordium, delete the recording you have just transferred to Goodreader (it is saved here, no need to take up more of your iPad's memory), and repeat steps 1-5 for each student:
6 - Once all is done, make sure that you have set up a shared folder in your Google Drive. It should be shared with your class:
7 - Select all of the named student feedback files at once. This is where Goodreader comes in useful as you would have had to of done this one by one if you exported directly to Google Drive from Recordium:
8 - Select upload and navigate to your Google Drive account, find your shared folder and put all of the files in there in one go:
The only draw back to this is all students in the class can hear each other's feedback, but sometimes this is a good way of doing things as students can compare their feedback with others.