The photos from @Dovefromabove reflect my thoughts: work vertically, with climbers, pots, tall plants etc. You could create a lovely ‘valley’ effect with lots of texture and colour.
If you have a garden and a library, you have everything you need. Cicero
What about stones to match what you have on your lower levels with random York stone pavers of different sizes, (B&Q have the pavers), as well as the fence painting, step fixing and pots as previously mentioned ...
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