in Scotland I use the scotrail service as they operate the trains, not sire what to do in England to be honest. Funnily enough, it used to be a Dutch company but the Scottish government got the trains back as they were terrible!
I am not sure what to do about Trainline in England, maybe you were just unlucky, the only thing I would suggest is to see who the operator is and if they have ticket purchasing facility!
Have fun up in Edinburgh and bring the sun with you, it is hazy again!