I actually think we agree here- maybe I missed something, but in the OP nothing says anyone was requiring tests. I would honestly be surprised if anyone ever requested that- even if there is something someone could do, I’ve never seen a vet “require” diagnostics for a pet that isn’t well. I would be expecting likely just a conversation or maybe at most a quick exam in a case like this.
As far as not being able to book it immediately for a non-client, well, that’s an issue that’s been discussed at length on these forums. They simply can’t. It’s a matter of protecting quality of life for staff, as well as protecting time so that they can see their own sick patients when needed, which many vets are already unable to do, to the legitimate disappointment of their existing clients. Again, that’s why it’s important to have that existing relationship, which it sounds like OP has- she just doesn’t want to drive that far. I completely understand that, but my guess/hope is that vet would be able to fit them in, whereas a new vet just can’t.
I think a home euthanasia service probably could do it sooner, as their business model is different- I hope that’s an option available to you, OP. I have not used one myself but have heard good things.
Edited because we posted at the same time- sorry for your loss and I’m glad it went smoothly.