If you didn’t travel, you can’t get DelayRepay, but you can have your ticket refunded if your train was delayed, or cancelled, or your reservation would not have been honoured.
Advance tickets are issued as single tickets and not returns, so as robbeech correctly observed above, your second ticket isn’t refundable if that train ran to time, although in the circumstances I do not expect there to be any issues obtaining a refund for both of your journeys.
You should address your request for a refund to whomever you purchased your ticket from, within 28 days of the day you intended on travelling.