Robins have become very adaptable in order to get their food. It used to be blue tits, etc. that hung onto the suet ball feeders but now robins seem to manage very well. They do have a good incentive though - feeding their young! They also love suet pellets that I put on the sundial - that's if the starlings haven't gobbled them all up!
Thanks everyone for the great comments and favs - it really is much appreciated and is very encouraging