  We prove that the cyclic and constacyclic codes constructed by Grassl and
R\"otteler in arXiv:1502.05267 are generalised Reed-Solomon codes. This note
can be considered as an addendum to that article. It can also be considered as
an appendix to arXiv:2106.10180, where Conjecture 11 of arXiv:1502.0526, which
was stated for Grassl-R\"otteler codes, is proven for generalised Reed-Solomon
codes. The content of this note, together with arXiv:2106.10180, therefore
implies that Conjecture 11 from arXiv:1502.0526 is true.
