You have the right as a patient to choose to be referred to a private care provider or alternative hospital trust. The care you have been referred for is normally the responsibility of the hospital specialist to arrange and not the GP. Any tests that your new provider requests would need to be arranged by them. You will need to be prepared to travel to your new provider to have all the tests, investigations, and interventions done that would normally be done by the hospital team. Your local hospital team would be expected to share relevant tests they have already done so there is no unnecessary duplication.