Posted: 12/10/2014 at 23:13
Chicken chaser, just cottoned onto this thread. Firstly, what a brilliant job you have done. Excellent. First class. I could jump in with plant suggestions but you have been given loads of ideas. Grasses I,would have said but they are on your list.
Height from perennials? Narrow verticals from veronicastrums, agastaches like black adder and lobelias like Tanya? Narrow shrubs like berberis Helmond pillar?
Wide borders are opportunities for a generous look in the garden but you could meander from your one metre to 2 metres occasionally because, as you say, 2 metres all round could look out of scale for you
The apple tree? Espalier trained is very effective and formal. Consider too growing as an oblique cordon if you have the right variety, viz., a spur bearer