Dave Plowman wrote:
The reason for these loop in etc ceiling roses is they are quick to
install and economical with cable. But you're not forced to use them - you
could do it the old way using junction boxes in a more accessible place.

The hassle I've had with people who've tried to replace a ceiling
rose and have been stumped with the multitude of wires sticking
out of the ceiling, then have proceeded to join all the reds together
and all the blacks together and wonder why the fuse keeps blowing,
the light is permamntly on, and the bedroom only comes on when the
bathroom is one. ... I always go out of my way to ensure then every
outlet has only a single cable, unambiguous cable coming to it (or
a single pair for sockets). The extra 25pences of junction boxes is
soooo owrth it.

In the OP's example, what I've done is trim a length of T&G to fit
over one pair of rafters over the ceiling rose/whatever and trim
off the tongue from it and the adjoining board so it just slots
into the space, and put a notch in it to lever it up.

JGH