The problem is waymarking falls into the trap of the rigidity of law and the flexibility needed to needed by common sense. This is compounded by the polar opposite interpretations of common sense as applied by occupier and visitor to the countryside.
That's bonkers! Why doesn't he just create a permissive path with signage saying "permissive path avoiding working yard/machinery/livestock"? Most people will gladly follow any sign that says "avoiding livestock" 
Unfortunately there is a large following among the 'rambler' fraternity of the pedantic 'I have a right to walk the right of way and must follow it precisely' school of thought. This frame of mind is widely used by the landowner press to strengthen their case that the user groups lobby is unreasonable insisting they have rights to access to the countryside.
An article in the March edition of the British Farmer promotes a scheme for diverting ways around livestock with temporary ways, (a 50 year out of date admission that the 1940's rules have been bypassed by imported breeds). However this initiative has the added impediment that it should be made into law, the occupier groups will cite cost of insurance against third party claims, a rod self generated by the owners of land to drum up support from working farmers for their own lobby group and beaten regularly over many decades because they know that the farmers lobby group is built on a framework connected with insurance.
As the conflict between landownership and land user has evolved the visitor has been caught in this multi-jawed vice of conflicting myths,
Maybe he secretly prefers the path to go through his yard so he can yap to all the people passing through 
There are some occupiers, who consider themselves great sages, this is usually based on articles in the agric/owner press that is poorly supported by any proper research on the part visitors to the countryside actually play in the rural economy and how the access network ought to allowed to evolve.
The local authorities can only way mark according rules interpreted from the laws. How these get confused is a mixture of reasons based on attitudes and viewpoints caused by infighting on both sides of the occupier / visitor divide. The real weakness is the social immaturity of the landowner case; the motivation they peddle is based on that of the spoilt child, who claims he owns the playground and the toys therein. Sadly signage become the victim, unlike Alpine regions, rural Britain contains many more destinations, a need to be flexible providing ways because of greater variables and the terrain does not govern the limit of potential routes.
As technology has developed to make new practice possible, the understanding of participants is still stuck in the quagmire of manorial rights and petty squiredom
