I don't travel much by rail these days except in London.
I'm completely out of touch with buying train tickets to
places like Birmingham and Bristol. In my day it was all
pretty simple; you just turned up and bought your ticket.
There was the very occasional special offer: a friend and I
went from Euston to Glasgow Central on an early train for
£5.00 day return! That was more than forty years ago! (We
wanted to visit St. Mungo's Cathedral)

There are web sites providing train fare offers but which are
the best ones? Am I correct in assuming that some will offer
less than ideal rates because they receive a commission from
train companies? Do they all work this angle?

All and any informed opinions will be welcome.