Thanks Jason, that's interesting
I have the sunny position, but no ridge unfortunately
The holly and ivy thing is not a problem. Several cuttings from a beautiful ivy that I found growing on Hampstead Heath have taken over one wall. And my Holly is growing from strength to strength.
Anyway, I'll order some Buckthorn plants. I'm getting excited just at the thought of designing the layout. And although my venture may not be successful, I can but try
Thanks again,
Ash