I think the Falken is even softer than the Yoko, maybe worth a try.
As I said, my experience of all the tyres is on the road, and mostly on country lanes at that. The A539 just doesn't seem to handle damp, greasy, muddy, leafy or wet conditions at all.
Its fine, if a bit of a screamer, on smooth and dry main roads, for me a tyre has to cope with far more than just a track though.
