Jeff Layman wrote:

Other thoughts - Cotoneaster dammeri, Daphne laureola, Euonymus fortunei,
Hypericum calycinum, Waldsteinia ternata.

Jeff, thanks! The Euonymus fortunei and the Waldsteinia ternata look
just like what's needed. The hypericum calycinum is good too but I know
it well and one of its negatives was the way it starts appearing from
crevices in walls etc. Whether its roots would travel under the
adjacent soil-retaining fence and then begin to appear between the
planks, I'm not sure, but I don't think I'll chance it! Love the
luscious denseness of the Waldsteinia ternata!

Eddy.