I have every sympathy with cattle farmers who lose animals to TB. I think more money should be put into developing effective vaccinations against TB, as this will prevent cattle catching TB from all sources, and should eventually develop herd immunity. I think the government should be funding this as a priority.
Whilst badgers are a source of TB infection, there is a lot you can do to prevent badgers getting into cattle sheds, and stop them being attracted onto the farm, as the main source of infection is badgers coming into cattle sheds in search of food or bedding. However, another animal which is a major carrier of TB in the UK are deer. Deer are more likely to share pasture with cattle, thus it's harder to prevent infection.
Plenty of other animals, including more exotic livestock such as camelids (including animals like camels and alpacas) can infect cattle with TB. Whilst cattle are routinely tested before movement, sometimes more unusual forms of livestock are not tested as there is less awareness and less restrictions. It is possible that when these animals come into contact (e.g. at an agricultural show), TB could be spread from the camelid to a cow.
Enforcing biosecurity on farms is really important for disease prevention. The government could perhaps put money into helping small scale farmers develop better bio-security (for example by providing grants for specific equiptment, or providing education on the best techniques). Large scale intensive farms are very hot on biosecurity, and tend to have less problems with disease (because infectious disease in an intensive environment is devistating).
I'm not against a cull in principle, although I do think there are other things the government could and should be doing (instead if it has to be a choice). However, I do think doing a cull in a small area is pointless. It will probably have one of two results (because culls in a limited area usually do)- either it will cause badgers to disperse from the cull area into the surrounding areas, causing, possibly, a rise in TB in those neighbouring areas, or, after the cull is over, badgers from neighbouring areas will move back in, redering the cull pointless over the long term.
I'm also worried about the effect of removing badgers from ecosystems, which doesn't seem to have been that widely investigated. Badgers act as an apex predator in lots of ecosystems, and it has been shown that the removal of apex predators often has unintended consequences for the ecosystem.
In this specific case, I would be a bit worried about the effect on mink populations. Badgers do sometimes compete with mink for food, so it follows a lack of badgers might cause an increase in mink populations, which we have spent a long time trying to completely eradicate, because they are a harmful invasive species. It will probably also cause an increase in other predator numbers, such as foxes.
I think the trials are so small scale and short term as to be pointless, and I wonder if the government are going to use this as an excuse not to go ahead with a wide scale cull and go back to ignoring the problem of bovine TB.