We stayed 1 night at St Athans, having a short stop in beautiful London, whilst travelling from Germany to North England via train.
The hotel is in a short walking distance from public transport (local, national as well as international) which was just perfect for us.
Nice, cozy and clean room - ours was very tiny, so staying there with quite a few bags and 2 persons total was okay for a short stay, but would recommend a more generous space when staying longer.
Staff was very kind and supportive.