I've been offered some proofreading work by a local University - to help a student for whom English is a second language, who has good spoken language but who has some problems with the written work. It is a science subject. I have done a little bit of proofreading before, but I've not had training and as I'm not doing it for a publisher I don't need to know any of the short hand etc. My question is, how should I charge - by the page or by the hour? And what would be a reasonable rate, given my experience? I am a graduate in an arts subject, who enjoys writing and English. Oh, and I'm not in London, if that makes any difference. Thanks in advance for any help!