@catsize Could you not have organised a train or hire car for the second leg? If you'd booked the return journey and had paid both ways before going or on arrival at airport, why didn't they cover their share at that point, especially as they were ones insisting on that method you'd think they'd have had the funds on them.
I've been in a similar situation but friend knew my income is a lot lower than hers and that it's very rare I can afford to pay for her share if something more expensive than I'd usually buy so she always makes sure I have her share before I pay, or she pays and I give her my share, she usually tries to treat me but I like to pay my way.
In your situation, if she was insisting on an expensive cab for transfers both ways and was paying half, her half would have been paid at booking both ways either on booking the break, or at the airport on landing, but if return hadn't been booked and she had to leave early, we would have used a cheaper method.
I wouldn't have asked for taxi money back either, but at the same time, I'd feel like a shit if I'd forgotten to pay for something I'd gotten a friend to book or organise on my behalf.
Was actually due to go out tonight and other friend had bought tickets costing £50 each, Something's happened being my control and I can't go, Ive given friend the money for my ticket and would have done regardless of the reason I can't go and how rich/skint she is. She'd never have asked but I'd never assume she should cover my costs because if changes to my life that have zero to do with her.
Id imagine it would have taken a lot to ask OP for the money she owes, and a month later is more than reasonable. It's sad you lost your gran and didn't get to use the ticket OP, your friend has been a good friend, she was going to support, she's left it a month before asking, you should pay and apologise for it being late. I didn't stay in my home the week after my gran died, still had to pay my costs for house, internet, water, council tax, even though I didn't use any of it. You need to pay what you agreed.
Surely you had the money to pay as you were you going up until your gran died? You haven't spent your ticket money on something else and now can't afford it?