Their reply to my request to delete my data:

Thank you for your email requesting your right to be forgotten.

In order for us to carry out this request, we require proof of ID to ensure we only action requests made by the genuine owner of this email account. Acceptable forms of identification are,

• Recent utility bill from the last 3 months (e.g. Gas, Electric)
• Valid drivers License
• TV License within the last 12 months
• Council Tax Letter within the last 12 months
• Title Deeds