Furthest distance for A Day Return ticket?

[jednick]

I know of some places about 70 to 80 miles from my home station where I can buy a Day Return ticket for the journey.

What examples are there of two stations 100+ miles apart where you can buy Day Return tickets for the journey?

What's the furthest known distance between two stations where you can buy either an Off-Peak Day Return ticket or an Anytime Day Return ticket for the journey?

Are there any anomalies where you can buy a Day Return ticket between two stations but they're so far apart that it would be impossible to do the return trip in a day?

 

[Merseysider]

You may find the following threads of interest, which hopefully answer your questions:
Off Peak Return and Off Peak Day Return Availability
Longest distance CDR?
General availability of day returns?
Minimum distance for a SVR (Off Peak Return)

 

[Darandio]

There was also this recent one discussin such day returns as Liverpool to Brighton, Preston to Edinburgh etc.

Why no day returns on some routes?