Problem type: Looks like the website has a bug.
Site owner: No
Steps to Reproduce
1) Navigate to: https://www.hotmail.co.uk/
2) Full info here: http://tiny.cc/mfbchx
As Gervase mentions they forgot “www.hotmail.co.uk” on their certificate but https://hotmail.co.uk/ works fine. The site should be contacted if someone wants to reach out.