I'm kinda new to gardening, and also new to my current area. I'm now living in central London and in my small garden I have a rosebush that I believe is a "Field rose" rosebush. It's not in great shape. There are aphids and tiny caterpillars on it, see pictures attached.
Could you please let me know if a) these are really caterpillars and aphids (I'd like to know what I'm up against!) and b) how to get rid of them