We've hiked through fields pretty much every weekend for decades, never ever had issue with cattle. We have had entire herds follow us, but mostly curious adolescent males. They usually follow about two metres behind and stop dead every time we turn, like they're pretending not to follow us. We've had the occasional nibble and some very friendly ones, but never an issue. Just don't spook them. Obviously don't get in the way of a bull and his bedroom antics, or between a mother and her calves, but even bulls when unaccompanied will mostly ignore you if you give them a wide berth. I think the only scary cattle thing we've seen was once when we saw an entire herd stampede. Fortunately on the other side of the field and they ran the opposite way, demolishing a hedgerow. There's been a couple of cracks of thunder earlier, so maybe they were spooked (though nothing at the very moment).
In my experience, horses can be more aggressive. But even then, if you threaten them back and stay out of kicking range, they usually retreat.
I don't think you can expect a farmer to run around changing all the signs every time he or she moves an animal. Bulls look like, well, bulls. They're not very good at sneaking up. Stiles break and paths get overgrown. Report them, eventually, someone will get around to fixing the problem, but it's a walk in the country, so expect some clambering. We always carry a pair of secateurs this time of year.