In certain places the NRCoC▸ refers specifically to the destination on the ticket; but in other places simply to "your destination station". There is also the question of what the relevant company's passenger charter says.
FGW▸ Customer charter says ...
If the train you are travelling on is delayed we will endeavour to get you to your destination station, with alternative transport provided if necessary
so that's Melksham
... however, I'm not able to be travelling on the train because it's been cancelled
Looks like it's academic for tonight. The place I'm training has a transfer bus to another site of theirs and I'll be using that - thus avoiding the need to faff about with local buses which would leave me pushed to get to
PAD» for the 19:00 .
Useful learning curve - I've always been very unclear about what to expect at times of disruption. Of course the real answer is for us to have a 100% perfect system!