But the OP has a CDR not a regulated Off Peak Return
The broad question of interpretation remains the same whether the ticket is a regulated SVR, an unregulated SVR, or an (unregulated) CDR- the literal wording of the restriction code plainly and unequivocally permits such travel, and the principle of
contra proferentem means that, even if ambiguity existed, which I dispute, the benefit of the doubt would go to the passenger.
Comparing:
restriction code G6 said:
Not valid on trains timed to depart the origin station shown on the ticket after 02:59 until 09:15.
with:
restriction code B2 said:
Not valid on trains timed to depart after 04:29 and before 09:15.
it is plain that the terms of the contract for travel are different, that the additional words as bolded in restriction code G6 must have meaning, and hence that their absence from restriction code B2, and also from restriction code B4, must indicate that the travel is subject to different, more generous rules.
Furthermore, the NRE website correctly states:
http://www.nationalrail.co.uk/times_fares/ticket_types/TicketAndValidityFinder.aspx
The general principle is that all tickets are unrestricted except for when the restriction code states the ticket is not valid - if it does not specifically state that it is 'not valid' then it is valid.
If a ticket permits BoJ, then it is natural that restriction codes will make provision for the restrictions applying when travel is made or resumed from an intermediate station; this will depend on the precise wording of the restriction code. For example, restriction code O7:
http://www.nationalrail.co.uk/O7 makes clear that journeys are permitted from intermediate stations, but that such travel does not benefit from the concession permitting travel on certain services due to arrive at Paddington before 10:00.
On the other hand, restriction code BX,
http://www.nationalrail.co.uk/BX,
Not valid on trains timed to depart after 04:29 and before 09:30 or after 15:30 until 18:16.
as used for XC CDRs, means that a passenger can start short at an intermediate station at or after 09:30, or at or after 18:16, even if the train departed the origin station listed on the ticket before 09:30, or, as the case may be, between 15:30 and 18:16, but cannot start or resume short at an intermediate station between 15:30 and 18:16, even if the train departed the origin station listed on the ticket before 15:30, so it works both ways, so to speak.