To obtain an EASA Part-FCL PPL(A), you need to do your training at an EASA-approved ATO. Which will have an approval to conduct a specific PPL(A) course.
The course now requires 100 hrs of ground training and each exam requires the ATO to sign you off as ready to take the exam. So it's no longer a question of learning the answers, taking the exams at a UK ATO and then disappearing to do your flight training in the USA.