Planting against the 'tower's' walls only began two-ish years ago, and already they are doing what has been asked of them.
I chose two good 'doer' Clematis for the least sunny walls, an evergreen climbing Hydrangea for the most shady, and a bog-standard Wisteria for the sunniest.
All are doing well.
And this is how the 'tower' looks today with all it's greenery in situ. I'm very happy with the result so far.