www.kingsleynapley.co.uk/comment/blogs/private-client-law-blog/why-you-should-appoint-a-guardian-in-your-will
www.birketts.co.uk/insights/legal-updates/appointing-a-guardian
See also:
brodies.com/insights/guardianship/key-considerations-when-considering-the-appointment-of-guardians-for-your-child-part-1-how-do-i-appoint-a-legal-guardian-for-my-child-and-what-do-they-do/
Power of attorney vs. guardianship: knowing the legal differences | Brodies LLP