What are my options?

You have three options. First, part-time courses offered by traditional teacher-training institutions - such as universities and colleges. Second, there are distance-learning courses, such as the one provided by the Open University. Third, there is no reason why an employment-based training placement cannot be part-time - as long as the school is willing. However, despite the growing number of options, this latter is not an easy route and with trainee numbers increasing there is no incentive for providers to expand it. You will need to consider whether you will be required to teach a block practice at some point during the course, and whether you would be able to manage that.