Hi Yen
I do all of Cathe's workouts

You are quite right about properties in London, not only is space a factor, but (in the case of everywhere I have lived here) the age of the properties is also a factor. Everything here is Victorian built, so creaky floors galore! I tend to find step is good because it takes up a little less room and the step cushions a bit of the impact.
But even after all these little annoying things, Cathe really is a results-viable, time and cost effective alternative to the gym
T