Have you got railcards?
If you haven't, then buy it/them before you buy your tickets. Returns to Edinburgh from Leeds are going to be £80-100 each, call it £170 total. You would get 1/3 off with a card, so that would be about £57.
Individual Senior railcards cost £30/year or £70/3 years but if you buy a 'Two Together' card it is only £30/year. With one of them then you could save £25+ on this one trip, and you'd make further savings of 1/3 on any other trips over the following year. Note: Off-peak only (after 09:30), and you both have to travel together for the card to be valid (the name is a giveaway!).
We booked two weeks ago because it will be bank holiday and it is Edinburgh Uni Graduation Day.Got a fabulous hotel booked,I am going to have a dram or two to celebrate.Oh, and you can use those on peak time trains too.