I am trekking to Northampton with everything that is not run-of-the-mill and surpasses my local general vet clinic's experience. A growing number of my piggies would not have lived as long and by far not as many of my piggies would have survived/come through operations as well without the Cat&Rabbit Care Clinic.
The Cat and Rabbit Care Clinic
The Maddocks are general vets specialising in treating only cats, rabbits and guinea pigs, and are therefore seeing a lot more of them than your average vet. While they can really make a difference in diagnosing and treating because of their experience and because they can keep up with reading up on research/veterinary developments in those areas, they are not miracle workers that can save every single piggy with a collection of serious problems.
Veterinary medicine, even super-vet clinics (which the Cat&Rabbit isn't), cannot solve every problem. The more vets can do and diagnose with adapting human medical methods, the more complex problems are turning up on the horizon. When the chips are down, piggies are still small animals with a small body and a metabolism on fast forward; especially once health issues are piling up and piggies are getting frailer.
Guinea pigs are also one of the most underresearched pet species because they have been too long seen as too common for an exotics species (as all small rodents are classed as) and as 'just a short-lived children's pet'. A lot of what is being done for guinea pigs today is on an experimental basis transferring from other species.
Just so you don't go there with unrealistic experiences. Even the Maddocks use referral vets for the super-duper stuff.
Kidneys are unfortunately an area where we are still pretty limited in what we can do when it comes to guinea pigs.