The easiest would be for her to talk to staff on the tube station, get a stamped note or something.

If she can't she should try recall times that she was on the tube. And we could try speak through to Line Control.

If it's me I will usually try my best to check the delay.

In regards to your 2nd point.

With advance tickets if they miss connections and it is the fault of the underground or other connections. (note if notification of service alterations available in advance this does not apply)
Providing there is prove, the customers ticket should be validated for the next available train.

FGW^▸ (First Great Western) have briefed all staff of this AFAIK^▸ (as far as I know).

Regards

Ollie

I do not travel the route, but could try get a rough idea, what sort of time would you be travelling?

Regards

Ollie