Looking into the history of the fares that I originally mentioned (Liverpool to Colne, Liverpool to Lancaster) it seems that Northen changed them from 8A restricted SVRs to SORs in 2008.
http://www.farehistory.info/history/Liv/Cne/
So we have gone from -
Pre-2008 (8A SVR) - no time restrictions, no outward BoJ, one day outward validity with travel allowed on day after if journey "cannot" be completed, return within one month.
2008-2016 (SOR) - no time restrictions, no BoJ restrictions, 5 day outward validity, return within one month.
2016 on (SHR) - no time restrictions, no BoJ restrictions, strict one day outward validity, return within one month.
What old Northern giveth, new Northern taketh away!
If they are so worried about ticket reuse then perhaps a compromise would have been to convert the SORs to 2T SVRs, rather than abusing the new SHRs which were supposedly introduced to offer "increased choice by offering a period Anytime return for use in the peak on short distance flows where traditionally only a Day ticket was available"? 2T SVRs would allow - no time restrictions, no BoJ restrictions, one day outward validity with travel allowed on day after if journey "cannot" be completed, return within one month.