  We study the topological properties of a kagome plasmonic metasurface,
modelled with a coupled dipole method which naturally includes retarded long
range interactions. We demonstrate the system supports an obstructed atomic
limit phase through the calculation of Wilson loops. Then we characterise the
hierarchy of topological boundary modes hosted by the subwavelength array of
plasmonic nanoparticles: both one-dimensional edge modes as well as
zero-dimensional corner modes. We determine the properties of these modes which
robustly confine light at subwavelength scales, calculate the local density of
photonic states at edge and corner modes frequencies, and demonstrate the
selective excitation of delocalised corner modes in a topological cavity,
through non-zero orbital angular momentum beam excitation.
