the one on the rose is black spot a fungal infection
the one on the sycamore is also fungal called tar spot.

different species of fungus and common at this time of year. don't compost the leaves as their spores will survive and then re infect. spray the plant with a fungicide soon after the leaves open in spring. apart from being unsightly it does little harm to the plant.

other plant may be fungal after sap sucking insects have wounded it.

Thank you,

I'll post some more pictures as this happened all through the summer. We remove all the fallen leaves from the roses and burn all the affected leaves/stems from the others to make sure it doesn't get in to the soil.

Is there an organic way of preventing the sap sucking insects? If not is there a non organic way as it really affected production this year.

Duncan

Companion planting may help as will encouraging birds and other insects like lacewings and hoverflies as their grubs prey on sap suckers. Ladybirds of all ages eat other insects too.
Avoid contact insecticides as they are indiscriminate. Any systemic insecticide sprayed according to instructions will help reduce their impact but they are all part of nature and many other animals rely on them for their own survival.