Cox is not really a good apple to grow that far north, it is a little tender and may not flower too well in the colder north. It is also self infertile so you need a suitable partner to get cross-pollination.
https://www.rhs.org.uk/advice/pdfs/applepollinationgroups is a good place to look for which trees to plant together.
Again Pears are reckoned not to do so well above a line drawn from the Trent to the Mersey. The flower early and are very prone to later frost damage. Ours only manage fruit in good Springs.
Sorry, not a lot of use really on varieties.

Suggest you contact Orange Pippin Fruit Trees (they have a website) who will advise on good varieties for different areas of the country.

Agree with Ob, although Cox is my favourite apple it's not the easiest to grow in just any area. I would suggest that you look for a good local fruit tree nursery to find which varieties are most suited to you locality. If you are looking for a cooker Bramley is the best but it needs two pollinators (triploid) so perhaps look for a dual purpose variety as one of your final selection. This is why varieties like Keswick Codlin, Scotch Bridget or Scotch Dumpling exist because they were bred to thrive in these locations.