Outbound delays, knockon to return journeys - what's the status?

[whole diary]

[grahame]

1. Joe (not his real name) travels up from Melksham to Swindon about once a week to pick up his granddaugher.  The 14:31 gets him to Swindon at 15:02, the 15:14 return trip having him back into Melksham at 15:39.  He buys a return ticket.

Sometimes, the train is late into Swindon and turns around very quickly, not giving Joe the time to collect granddaughter from [other responsible adult] waiting outside the station, and he's then stranded until the next return train at 17:36

Question - he's bought one set of travel in a single transaction. An early delay has mucked up the rest of the plan, and he has allowed over the margin of connection time in Swindon.  Is he able to claim "delay / repay"?  Could he request alternative transport, bearing in mind the 2 hour wait he otherwise has to endure?

2. Graham (this is a real one) travels from Melksham to Harpenden on the first off peak train, but is significantly delayed on the way. As a result, he's also late leaving Harpenden on his return journey (a certain amount of time required there) and misses the train he had intended to catch on his return, which was the last train on which the off peak fare was offered by the GWR^▸ (Great Western Railway) website for a number of hours.

Question - is Graham allowed to travel on the next train originally offered on the booking site on the ticket he holds, bearing in mind he is only there for the "peak" hour service because of an earlier delay in a journey part made on the same return ticket?