Probation and Parole: Understanding when Eligable for Parole

My question involves criminal law for the Country of: England

Hello,

I was hoping someone could help me understand the release date notification slip.

the details are:

Sentance calculated on: 08/02/2017

Key Dates Non DTO
Number of days in sentence: 5295
Sentence expiry date: 07/08/2035
Conditional release date: 05/02/2031
Parole eligibility date: 07/08/2025
Licence expiry date: 07/08/2035

Could someone please explain:

• what key dates non DTO means
• what conditional release means
• what date he can actually apply for parole

Thank you for you time.

Probation and Parole: Understanding when Eligable for Parole