15 pounds an hour sounds very cheap. I know some people who are earning 50 pounds an hour as online tutors. Online tutoring requires special skills, over and above the knowledge about the subject area. This became very clear while the NOF ICT training scheme for teachers was in operation from 1999 to 2002. The scheme was hammered both by OFSTED and by many trainees who took part in it. Those training agencies that attempted to deliver their training mainly online came in for particular criticism. Trainees often felt isolated and tutors were overloaded. It was estimated, for example, that a tutor could not cope with more than 30 trainees at one time - i.e. about the same number as a teacher can cope with in a face-to-face situation.
The Institute of Education in London offers a diploma course in Online Education and Training:
http://www.ioe.ac.uk/english/OET.htmThe spectacular crash of UKEU last year indicates that online courses are probably not as much in demand as people thought they would be. UKEU failed to recruit enough students to make it viable. In addition, the target audience of online courses has not been thought through very carefully. Most people who follow distance learning courses tend to be in their 30s and 40s: v. the experience of the Open University in the UK.
Offering private tuition online to children is quite different, of course. It might work in some subjec areas.