We were asked about these recently, so thought it would be good to share the answer.
Festive cooking workshop and lunch on 9th December near Kingsbridge.
Christmas baking day by International Macrobiotic School on 3rd December. They do quite a few courses, some of which are vegan, but I would check first to make sure.
Christmas-themed vegan workshop on 9th November at Perrylicious in Teignmouth – this is fully booked but they might have a reserve list or have more coming up?
I attended a cake decorating course at Exeter college in 2014 and it was easy to do it with vegan ingredients. The cake above is an example of what I did on the course. Their latest course (31st October) is on the link above, definitely worth contacting them first to make sure that you can do everything vegan.
If you want a more intensive (and more expensive) course, check out rouxbe.com who do a plant-based professional course and a vegan baking course. All courses are online so can be done from anywhere. Note that not all of their courses are vegan.
If you know any other vegan cookery courses coming in Devon please add them in the comments.