The problem as I see it is that Railcard holders will have no incentive to travel GCR as they do with Hull Trains who not only provide lower fares but very low when the railcard discount is factored in.
Yeowart, as a I understand it, wants to do things the old fashioned way, and keep fares as low as possible, while retaining flexibility, against the current trend of moving to an advance purchase, book ahead railway, its a laudable goal, but I do remember reading some statistics that 80% of Hull Trains business is book ahead advance purchase fares.]
As I see it the problem that GCR faces are two fold:
1) £69 return for the leisure market is quite pricey, when that can be slashed in half by advance purchase. For this weekend for example, I can get APEX GNER tickets from Sunderland for £59, at times which are more suitable and condusive to a day trip. If you also consider that National Express and MegaBus both operate extremely low fares on this market then again £70 is expensive.
2) The problem I see with the business market, particularly from Sunderland is that Sunderland station doesn't have car parking, but quite simply, Sunderland city centre and the immediate surrounding areas are a dump, Hendon, Pennywell, Southwick, Ford Estate, are all very unprosperous areas. There's only Barnes that would be considered the "Posh" end. The point I am trying to make, is that the sort of busy professional, who works in Sunderland, is very unlikely to live in the city centre, and much more likely to be living on the A690 corridor to Durham, and commutes in to Sunderland by car, so when they have their meeting in London, they're only a short hop from Durham station, with its half hourly service, and they dont really care what the fare is, as its being put on the expense account anyway.
As already mentioned, if a passenger is paying £69, plus two £15 supplements for the 0646 ex SUN and 1650 ex KGX, then surely, it would make more logical sense tow pay the extra £45 and get the Business Saver, allowing you a later departure from Durham, with a comparible arrival time in London, contrasted with departing any time you like for the return, so if your meeting finishes early, or late, you're not penalised to travel at a different time.
If GCR had a better spread of services, say a 1500, 1700 and a 1900 departure, then the logic in their concept becomes more apparent, but untill they get those extra paths, their services are always going to be more attractive to the leisure market.