I didn't. Mostly because unless somebody is giving you a £1m start-up capital, you will have plenty of time to learn as you go because you will learn each new skill as you go. Sales and branding are just as important as business knowledge, so it isn't even is as if one year long course will cover all your needs - it varies so wildly from industry to industry.
There are plenty of websites offering business-startup advice and even one-to-one day-long crash courses in getting yourself up and running. What's your industry? I know of quite a few resources in my own industry that I can share.