That's likely against all sorts of health and safety regulations . Having said that, there lots of small business in the UK being run from storage units - eBay shops, mail order, and even a karate training IIRC.
Edit: links
http://www.bbc.co.uk/news/business-25336446 https://www.safestore.co.uk/blog/2016/07/martial-arts-self-s...