Hi Jannet
Brogdale do a design service for anything from 10 trees to 100 - you
may recall they did Sarah Raven's Orchard on the special Gardener's
world.
Your soil is challenging for fruit trees, anything more than 7.5 tends
to make the tree a little chlorotic. There are a few cultivars that
prefer alkaline soils -Branack Orange, Red Charles Ross and Saint
Everard spring to mind.

I like Martin Crawfod's book Directory of Apple Cultivars, it may cost
£25 but I've got my moneys worth from it. If you can get it from the
library then yo can see it for yourself.

Fruit yield is dependant on how you train the tree - and what rootstock
it is on. Commercially, on an M9 bush tree (5-6ft tall) they expect
to get 55 apples from the tree. The trees would be spaced
The current commercial trend is towards "super spindle" trees which are
2m trees that are permantly steakes or against a cane on a post and
wire system. The trees are spaced 1m between trees and 3m between
rows. These trees come into fruit early - two years after planting
yileding 4lbs going to 20lbs in year 6. Now for a glorified stick that
is a high yield.
Whilst a mature standard tree will yield over 300lbs of fruit, it is
difficult to manage and do you want that weight of just one variety -
when there is a choice of trees that can yield fruit seaonally.

Bramley is a triploid (three sets of chromosomes) so meeds two
cultivars to pollinate it - as I think you know - your idea of having
cordons is practicable.

I do knot know of a book that groups apples by type. As for the apple
tasting yes get yourself off go to one!!
http://www.commonground.org.uk/appleday/a-events.html

If I can help let me know

Clifford
Bawtry, Doncaster, South Yorkshire