The CCT is the Cambridge Cavy Trust. They are rodentologists and know a lot more about guinea pigs than most vets. Vets don't have to learn about guinea pigs as they are classed as exotic animals and treat them the same way as they would any mammal not taking into account ailments that are species specific to guinea pigs.
There is something on here about the CCT. If you can't get there, they will be able to tell you if there us a trained rodentologist in your area. Also if you text Vedra, she will text you back and tell you when to call her and she can give advice over the phone but obviously, paying the membership fee (£25 a year) helps them carry on the good work they do.
Here's a link to tell you about them
http://www.diddly-di.fsnet.co.uk/Links-Health.htm