I've just seen it with my own eyes.
We're all downstairs, the sun is shining and the Daddies are having a chin wag and River's asleep on her back on the floor right in the pathway of the sun, usually Saturday lunchtime, until there out of the corner of my eye I saw some movement up by the sunshine shed.
At first I thought it was George, the cat was moving forward but when he stopped and turned there was no mistaking, Flash Ah ah.
I watched for a while, hidden amongst the bric-a-brac on the table, he jumped across onto the other shed and then after taking a reccie of the area moved up past the Swinging Heart of Love, how dare he, and then into Squirrel Tree. I will spread the word as soon as anyone walks by.