You will find plenty of courses on the internet. Type in Dog training in Google. You Tube is also a very good source.
There are many home based training courses. A very well known training course is The Chartered Institute of Marketing. This is a well recognised qualification that you can do from the comfort of your home. There aren't usually any exams involved, this may depend on the level. But usually all of the qualifications are course work based.
You can also study for a Btec National which is an equivalent of 3 A levels. This can be in humanities subjects, as well as Business studies and many more.
Home Based Courses - ICSLearn.co.uk
This is a very well known college which allows you to study from home. You will have a tutor that will support you through studying. So sign up straight a way and good luck!