I'll preface this by saying that earlier in the weekend we'd played 2 really good rooms (at RADA and Escape Plan) so maybe the bar was set quite high by the time we played at Escape London.
The build quality of the room was pretty high; it's quite clear that a good amount of time and energy has been lavished on the construction and dressing of the room. It looked great.
The puzzles, though, I found (similar to the other room at this venue) to be glorified taks lists with instructions either written on the wall or given audibly. Personally I find that the a really good puzzle is one that requires a minimum of explicit instruction; it has enough signposting to get you on the right track and then an intuitive design that helps guide you through the steps to the solve. That's when I feel like I've achieved something and the fun kicks in.
I didn't get that with this room and when the GM asked the predictable "so, what was your favourite puzzle?" question at the end, it was a real struggle to come up with an answer!