The ARU Harvard reference guide lists guidance on referencing Email correspondence under the "Using electronic sources" heading.
It first mentions that permission to quote/reference the correspondence should be sought from parties involved. To maintain the anonymity of your assignment, we would suggest speaking to your tutor/lecturer to ask for their guidance, as it may be possible that you could place the word "personal email address" (or something similar) instead of your name in the reference.
In the Cite Them Right Harvard reference guide, guidelines on referencing email correspondence can be found under the section "Communications", subsection "Public notices and personal communications" and heading "Personal communications". The guide also states that "You may need to seek permission from other parties in the correspondence before quoting them in your work. You might also include a copy of written communications in your appendices or note where the communication/correspondence can be located (for example, ‘library’). ", so it might worth consulting your tutor/lecturer about it.
