The medical secretary at my practice couldn't find my full records as I've moved around in the past, including overseas, (although that might not be why they are missing) but anyway she came to a standstill on it so I made an appointment with a nurse at the practice and asked her instead. She printed out the patient care summary immediately, for free, which only covered 2012 onwards. I emailed Visa Medicals to double check and they said it was okay that i didn't have full records, to just bring what i had and they could take it from there. This could be because i have no ongoing medications or conditions, but i would advise a quick email or call to Visa Medicals if you are unsure. They can even do a blood test on the day you visit to determine which vaccines to give you (i didn't have that though). What i did have however was old cards from when i was a child that showed my vaccinations, which they made copies of. At no point did i need any kind of signed document or doctors signature. I've read from others on this forum that if you have an ongoing condition its best to get a doctors cover note/letter to give more details, outline treatment, and support you are not a danger to yourself or others etc.