al wrote:

When you say to buds, all the buds are on the end of branches ... or am I
getting what are unopened flowers confused with something else? At the
base, the bushes have substantial, branchless trunks - it is this far that I
want to cut it back to. Will this kill it? Should I stick a couple of pics
up to explain better?


Buds in this context means 'nodes' the positions where leaves are/were.
If you look just there, at each node you will see a small (often red)
'bud' - sometimes quite flat, sometimes prominent. This is where you'll
get new growth if you prune just above it. With roses you normally get
new growth from 2 or 3 nodes below the pruning cut. In old wood you
can't always see the nodes but if you are in radical pruning mode you
can often get away with making a random cut which may or may not force a
dormant bud to shoot. Roses are hard to kill but please remember the
type of pruning you're proposing is a 'kill or cure' treatment - mostly
OK but you could lose the odd one. Something a skilled gardener could
make an educated guess on if they are able to see the plant in the flesh
rather than in a photo.

Rod