Cheshire Cat: Thank you for your positive response! If you check my profile you will see that I already hold the licence and ratings to which you aspire, as well as another pretty demanding job. Quite how you figure this as weak (note the spelling) is beyond me. The time I spend part-time instructing has left me in no doubt that the general level of remuneration in Flying Instruction is appalling, particularly given how much it has cost you to get the ratings in the first place. If you know better or have a firm offer then I suggest you hold on to it because I suspect they are hard to come by.
The point of my post was that you should not expect to make a lot of money from doing it, but if, like me, you find it rewarding to teach people and see them grasp a concept of which they had no idea before you told them, then go for it.
Oceanic Clarence (the cross-eyed lion?): You might get some more detailed advice regarding the exam options from the likes of Noggin or BEagle if you post on the Flying Instructors Forum.