In response to a previous poster, TfW still have the "do not use" seat covers out in force. And still on almost every seat (every airline seat, and 3 out of 4 table seats, not to be used), although some do appear to have gone missing. And increasing use of security guards patrolling the trains after each stop, but only to monitor face mask wearing - they don't seem to be bothered what seat you are sat in. Although they might be reporting how busy the train is to the guard, who (in addition to both TfW's and the Welsh government's recorded covid announcements in both welsh and english) makes an "important safety announcement" to let us know if there are too many people on-board for social distancing, followed by a string of announcements about not using the aisle seats even if you are a family travelling together, we will now be calling at all request stops as the train is too full for people to safely walk through to ask for them, etc etc. All repeated after every stop.
Compared to the Avanti service, where the guard very politely thanked us all for wearing our face masks to help protect each other, and for not sitting in the aisle seats, rather than officiously instructing us as TfW seems to do.