They don't have to pay you anything on top of salary for you to attend a course, apart from any expenses you have genuinely incurred that you otherwise wouldn't incur.
However, it isn't reasonable for the company to ask you to pay back any course fees if you leave, because it is a fait accompli - they have requested you do the courses, it isn't an option.
If you'd have asked for the company to pay for a course, then it would be reasonable for you to pay a return fee upon leaving after a short space of time.