Learn English – The bodies have been (were) sent to hospital: difference in meaning

Had you been is incorrect here. It's the past perfect and it's used when you're talking about something in the past and you want to make reference to something that happened even before. E.g. He told me he had been admitted to hospital.

But you could choose between were or have been, depending on the situation.

If your friend is fine now, you should use were you admitted to hospital or not?, because it's something that if it happened, it has already ended. This is the past tense.

if your friend is still ill and you want to know if he's in hospital or in bed at home, you should ask have you been admitted to hospital or not?, because in case he is in hospital, he would still be there; the action has not ended yet. This tense is the present perfect.

"I have been said it" is grammatically incorrect. As said is past tense it would just be "I have said it" or even "I said it".

The difference between "I have been saying it" and "I have said it" is that the former denotes multiple instances. With "I have said it" then the thing it is referring to could have been said just once.

In terms of grammar I said/I have said is past tense, whereas I have been saying is perfect tense.