In uk.d-i-y, BillR wrote:

Really good luck will be required based on experience of friend who tried to
fit this type of light in Vic flat. He ended up replacing the ceiling
because it was in such a poor state that working on it caused major damage.
You could assess state of ceiling by removing existing rose and judging if
its sound enough to proceed.

On The Other Hand, I had no particular problem in our previous place, a
1920s semi with lath-n-plaster ceiling; rather than a power tool I just
used a padsaw-type blade (a sticky-out-saw-blade some 4-5 inchces long)
sold to go with yer typical Stanley knife. Treating the blade as
disposable, i.e. to be used up on the one job of putting in 5 ceiling
lamps, taking the job neither ever-so-slowly nor at a rush, and concentrating
the effort on the pulling-down stroke rather than the pushing-up, I
had no problems. The same blade cut through the plaster and the laths,
though I did drill a little ring of holes into the plaster to mark the
cut and to reduce the amount of blunting plaster the padsaw blade would
encounter. I did put the lights quite deliberately close to the
joists above (we had the floor in the bedroom above exposed at the
time, and quite a few boards got lifted and replaced with screws) to
reduce the amount of flexing going on.

So hey, you might just get lucky ;-)

Stefek