I need some advice!

I have a wall of about 6 Ceanothus shrubs...well, small tree's really! They have been in the ground for about 4/5 years max and I want to get rid of them. They take up the whole of the back wall in the garden and they just annoy me!

They are pretty established though ~ I took a hacksaw to them last year and literally cut them back to the main stem in an attempt to control them but they are huge again.

Can anyone give me any advice on how to get rid of them please? I am guessing I should cut them down to a foot or so but I'm not convinced that I will be able to get the roots out easily. On the other side of the wall in my neighbours garden are lots of trees and I would imagine that the roots would be intertwined with those...

Any help pretty please???