It's so lovely to hear about people planting lots of fruit trees! 
One thing to bear in mind about training fruit trees, i.e. not just planting them as standard trees but shaping them into fans or cordons or espaliers - is that you need the appropriate rootstock.
To explain a bit, just in case anyone doesn't know - when you buy a fruit tree from a proper nursery, what you're actually getting is a grafted tree, so you're getting a standard rootstock + a variety of apple or pear (or whatever). The rootstock controls the height of the final tree, the variety controls what kind of apple of pear it is.
Now, it might sound like you're making a small fan or espalier (or whatever) so you want a really dwarf rootstock. While that seems logical, it's actually wrong! You want quite a vigorous rootstock because you're pruning the tree like crazy to bend it into that shape. So something semi-dwarfing (which is sort of in the middle of the size range) for a smaller trained tree, or something vigorous for a bigger one. Something like an MM106 is perfect for an espalier apple in a standard back garden where you want three or four tiers. If you're looking to create something bigger, an M26 (rich soil) or M111 (poor soil) are good choices. For pears, Quince A (large) or Quince C (medium).
The cheapest way to buy these trees is to do it yourself. It's easy, but it takes a bit of guts. You start with either a 'maiden whip' (basically a tree that's a stick, with no branches) or an 'unfeathered maiden' (which has two branches at the bottom, which you want to make sure are at the right height for your first tier). You then gird your loins, take a deep breath, and send it to the guillotine, chopping off its head to just above the point where you want your first tier (unfeathered) or second (feathered). There are lots of Youtube videos that explain the pruning process better than I can without pictures!
I would recommend doing this yourself rather than buying ready-trained trees because it's way cheaper and more satisfying and you will have to learn to prune them anyway (unless this is delegated to a gardener, which is totally cheating
). The more you understand about how they are constructed, the easier the subsequent process will be!