There are persons on youtube who have done videos on Premier Inn Standard and Plus rooms. There are also videos on the Premier Inn County Hall and Waterloo. I did not look for the location that you are asking about.
I will be honest and tell you that the videos are somewhat discouraging.
I have also come across reviews about the coffee machines and pods. There have been more than one indicating that PI was stingy when it came to the number of pods that you could have. One person has written that he / she went to the front desk to ask for more pods and was told "no, that they had been given all that they were allowed for the day". It was not indicated whether the person wa sin a standard room or the Plus Room.
I put some stock in reviews but I also allow reviews to go in one ear and the other. Some reviewers may be hoping to get some money returned or something free next time they travel if they write a slashing review. Others, even on reputable sites, may be working for competitors and, yes, they stayed at such and such a place but it was so they could later write a negative review.
How does one explain that some people have the best time ever while others write "Worst Hotel Ever"