MatSnow, darlingmummy and petal. It is definitely cats. We have a family of foxes living just over the wall in a nearby pile of old railway sleepers and they regularly leave little gifts on the paving. The smell and consistency is vastly different to that of a cat and, quite apart from that, I see cats using that section of the garden bed but short of shooing them away, I cannot seem to deter them.
I had heard the lion poo deterrent many years ago and collected some when on a visit to Longleat, but it made absolutely no differene whatsoever - and the garden smelled like a zoo.
I've tried scented cat repellent pellets, powders, sprays, string, cotton, holly leaves and even studded the area with vertical 6inch lengths of bamboo, but to no avail.
I'm thinking of blacking up and putting on my camouflage kit and lying in wait with a pump action water pistol like Sylvester Stallone!
Fortunately, due to some clever gardening using strategically placed hedging and walls, the foxes cannot get into my back garden which is the prettier bit where we tend to BBQ and sit with a glass of vino, so I guess it could be worse!.