I have recently built a pergola and planted 4 roses about 6 weeks ago,
one on each of the posts. They are growing well and started to flower.
The roses were 2 'Generous Gardeners' and 2 'Falstaff' from David
Austin. Great scent and large blooms. However the 'Generous Gardener'
are starting to get covered in what looks like a very small black
beetle/ladybird looking insect about the size of pin head (not blackfly
or any kind of aphid). All the insects are inside the bloom not on the
leaves stem etc. The petals are turning brown at the edges and are
falling. Has anyone experienced this? This is on all the blooms, both
the fully open and also those only just emerging.

Any suggestions?

( The roses were planted in a large hole with lots of well rotted muck
and have been watered well. )