You can be registered as a temporary patient for up to three months. This will allow you to be on the local practice list and still remain a patient of your permanent GP. After three months you will have to re-register as a temporary patient or permanently register with that practice.
To register as a temporary patient simply contact the local practice you wish to use (you will need to be in the practice catchment area). You cannot register as a temporary patient at a practice in the town or area where you are already registered.
Download the Temporary Resident Registration Form