The message
from Victoria Clare contains these words:

I'm looking at planting up a fairly large area (say 5m x 12m) with minimum
care shrubs.

I quite fancy planting some Elaeagnus x ebbingei, having read the ecstatic
writeup at http://www.scs.leeds.ac.uk/pfaf/elaeagns.html, but how invasive
is it?

YMMV, but eleagnus ebbingei isn't invasive at all here in Scotland.
Ebbingii is the taller one with evergreen dark green or variegated
leaves; you might be getting mixed up with e.commutata which is smaller,
and has elegant deciduous silver leaves. E.commutata does sucker but
never enough to be a nuisance IME; I also found individual plants aren't
very longlived in a wet climate so was glad to have a supply of new
ones.

Back to e.ebbingei; when I go over to the mainland, there's a scruffy
working area between the port and the train platform which is bordered
by rusty fences, backed by an rough unkempt hedge of eleagnus ebbingei.
The beautiful soft scent of its winter flowers fills the air all around
atm, but they are very tiny and concealed under the plainjane foliage.
It always makes me smile to see travellers' heads turning this way and
that trying to work out where on earth the heavenly whiff is coming
from.

Janet. (Isle of Arran).