I'm often asked to advise on fruit trees suitable for the northern parts of Scotland,
The most North growing apple in a way is Coul Blush which originated in Ross shire.
Beauty of Moray is well suited, to Elgin, Forres, and the north east.
James Grieve (named after Nurseryman James Grieve of Edinburgh) seems to do very well in and around Inverness, and the Black Isle - as does Discovery, Katy and Fiesta
I tend to suggest to people that its sensible to plant fairly early ripening varieties such as George Cave, Starks Earliest and White Juneating - so that they will have time to ripen up.
Generally its sensible to plant a range of varieties as what usually happens is that different trees succeed in different years
there are lots of notes on the stocklist which you can find on the ordering page of the website https://www.scottishfruittrees.com/ordering