I would reiterate to them that you broke your journey intermediately and resumed it at Bridgwater, meaning anything before then is irrelevant. I wouldn't even tell them about what you did before then, it has no bearing on your claim.
They insisted on full details of my day's journey otherwise wouldn't process claim. They have now finally approved the claim. It's only been given at 50% of the return cost, but it's still a good outcome. It's technically correct, if a bit pedant's corner
Intended was Bridgwater 19.46, reality was 21.44
As the connection was 10 minutes tighter at Exeter on the later train, it's been downgraded as 1hr 45. Not ideal given departed 2 hours late, a long time to be stood there, but it's technically correct (if harsh). I'll consider this one closed