Trainline - vastly different prices on site and in app

[Roundaboot]

I'm trying to book train tickets for this Saturday on Trainline and getting significantly different prices on the app vs the site for the exactly the same trains. Same number of people (2 adults), same number of railcards (1 16-25 card) but on the site it's given me £115.64 total vs £63.09 on the app.
Has anyone experienced this?

You're not looking at advance tickets vs open returns are you?

Nope, but on the app it seems to be applying SplitSave to both legs of the journey, whereas on the site, the return leg is Advance Single

Try looking on Scotrail, they sell tickets for the whole country. They don't charge any fees and you can benefit from split save.