Green flies of two colours sound more like they could be aphids at the winged stage (later adult stage), they come in various shades of green and brown but all similar body shapes (with a larger rear end compared to their head), even though some will not have wings and will be very small when they have just hatched. They're usually about 1-2mm big. Small webs could be spider mite, but also could just be spiders which I often find on my own roses. Usually spider mites are a bigger problem in greenhouses/indoors, the latter of which is usually not an ideal place to keep roses anyway (they prefer more humidity, but not directly sprayed leaves as this can spread disease like blackspot). See: www.rhs.org.uk/biodiversity/indoor-plants-sap-feeding-insects . Where are you growing these roses?
The weird thing is neither of these creatures usually 'eat' roses, as in, you wouldn't be noticing any bites out of any of the leaves, though they do both feed on the sap. As I say, spider mites you usually just end up with discolouration and eventually general weakening of the plant (early leaf drop), and aphids suck the sap from roses usually at points of new growth (new leaves, rose buds), which can lead to deformed leaves/buds and restricted growth in the future, also a sticky and shiny residue left on leaves with bad infestations, but not noticeably 'eaten' leaves.
Again, if the damage is minor and your rose is outside, then aphids usually get eaten fairly quickly so you can physically remove the ones you can see and the problem should sort itself quickly without much further intervention. So long as you are not overly reliant on pesticides and have killed all their natural predators. With spider mites, if it is them, I would again suggest moving your rose outside, especially if you are in the UK with our current weather atm. If you can't do that for whatever reason, there are suggestions to deal with them here: https://www.rhs.org.uk/biodiversity/glasshouse-red-spider-mite
I probably can't help more without photos and more context at this point I'm afraid.