Don't grow them myself - from the description, they look just like a normal cordon trained tree. Great for very small gardens, this is a single stem, with the potential for fruiting spurs along it. I'd comment that Bowers look a little on the expensive side, at £17.95 for one tree, and also there is a £7.50 delivery charge.
I can't see how old the trees are that you're paying for, so don't know if this is good value for money or not. I would expect the trees to be ready trained and at least 3 years old at that price.