I would suggest that you write to your MP and ask for them to get in touch with GWR requesting the easement to be extended until such time as they restore the first service of the day. This process will unfortunately take some time.
If your MP receives a negative response I would see if you can deploy your powers of persuasion to have them write to the Rail Minister or Secretary of State. They can then politely point out that, to use the words of
@Bald Rick the railway is a public service - and they should, if you agree with that view, act in the public interest even where it's not in their narrow commercial interest.
The government and GWR may refuse to do so even then, of course. But you won't know if you don't try.