To plagarise my own posts on the linked thread, my view is that it would be valid to travel on the 09:01 from B, assuming BoJ is permitted.
For example,a Filton Abbeywood (FIT)- Swindon (SWI) CDR takes restriction code W1 and is valid, subject to appropriate time restrictions, to start short at Bristol Parkway for travel to Swindon on a train from South Wales to Paddington.
Clearly, the "by any train except those timed to depart before 0930" restriction on this ticket must be based on the time at which the train is timed to depart from the intermediate station, in this case Bristol Parkway- after all, the train on which the passenger has travelled has not departed from Filton Abbeywood at all, and, in the case of "starting short", neither has the passenger.
The alternative interpretation, of applying the time restriction based solely on the origin station listed on the ticket, would mean that a FIT-SWI CDR is valid on any train from Bristol Parkway to Swindon that has not physically travelled via Filton Abbeywood, and I doubt very much that FGW would agree with this!
This interpretation would also produce the absurdity of a person wanting to start short, or resume, at 2100 at Truro on the 0820 from Aberdeen to Penzance being barred by a 'morning peak' restriction, (and would arguably contravene fares regulation on that particular ticket, being a regulated SVR), and would also mean that a SVR from Pilning to [anywhere] would be unusable on a weekday from any intermediate station, which would clearly be absurd.
What would happen if a passenger has not "started short", but instead made a shorter-than-advertised connection?
Some restriction codes, such as G7:
http://www.nationalrail.co.uk/pdfs/CDR_G7.pdf
do state:
"By any train except those timed to depart the origin station shown on the ticket before [time]..."
others, such as H7, name specific stations from which restrictions apply to joining the train,
and still others, such as B3, state:
http://www.nationalrail.co.uk/pdfs/SVR_B3.pdf
"By any train except those scheduled to depart before [time]"
(in this case, 0900)
Since words in contracts, and presumably restriction codes, are normally assumed to have meaning, the absence of the words "the origin station" in the latter code, and the further absence of words restricting BoJ, implies to me that "starting short" at or after 0900 at an intermediate station is permitted on a "B3" CDR.
In relation to Indigo2's question in the linked thread, my answers would be:
(2) 0905 and (1) 1001 respectively.
