No.
As per the Terms and Conditions, you can only gain a refund on a wholly unused Off Peak Return.You can't get a refund on only one portion, as the second portion is generally worth only £1 (or less).
It's only the expiry of the RTN portion that matters here. It's in the Manual, and the Conditions of Carriage.
Can you point me to the Terms and Conditions in question? I haven't seen anything that stipulates refunds are only available on wholly unused tickets.
According to National Rail Enquiries:
"
Getting a refund and cancelling a ticket
With the exception of Advance tickets and some special offers where refunds are not available, a ticket may be refunded before travel. In the case of a return, the return portion may be refunded while still valid. A refund fee may apply.
You can get a refund by returning your ticket to the place you purchased it. If this was a ticket office, you'll need to complete a refund application form. If this was over the telephone or the internet, you should return it by post with a covering letter."
Although this seems to support the "from date of issue" argument.
The conditions of carriage do seem to allow for refunds on partially used tickets:
"
The amount of the refund will normally take into account any use you have made of the ticket and in some circumstances no refund will be paid."
which is what I was referring to in the final paragraph of my last post.
And what is the 'Manual'? Where does one obtain a copy?
So what you're saying is, that despite the outward portion expiring on the date of issue I can ignore that and make refund claims up to 28 days from the expiry date of the return? Or to put it another way, up to 56 days from the date of issue/outward travel?
It would be useful to see where this is written in black and white.