Does the Uber app show the train as calling there?
If it does, you could make a complaint to Uber on the basis that, although you didn't obtain that itinerary, if you did a subsequent search to see if the tickets were valid on another train, and it suggested it was, then you have a case against Uber for misinformation.
However, if it was a completely different app, which you have no contract with, then it's probably best to not do anything.
I am pleased to hear you were not charged anything, and that BTP didn't see fit to attend such a petty matter. It is disappointing to see Avanti staff behave in this manner, but not surprising.
Unless you know exactly what to say, I would leave it; I do know of some people with legal knowledge who would consider submitting a complaint about their property being grabbed, and I am aware of hundreds of pounds being paid out for an incident involving Greater Anglia, but if you don't have that knowledge yourself, it's not worth pursuing that.
In future, you may wish to consider buying from the forum's ticketing site in future; while we can't compete with Uber in terms of cashback, we do provide a better product, and much better customer support!
Also, if in doubt regarding the validity of any ticket, this forum is a good place to ask.