Flight Compensation - Documentation to get sent compensation

I used the template letter and wrote to the airline who have said they'll pay me (and travel party) compensation for our flight delay but they have asked for the following in order to pay out:

1) copy of passport for each adult
2) bank details for each adult
3) copy of child's passport, marriage certificate of parents and birth certificate to prove kinship (if compensation is to be paid into parent's bank account.

Do I have to send all this information? It worries me sending so much personal information, especially due to fraud etc.

Can anyone let me know if they had to send all this to get the compensation? is this the normal procedure?

ps I've spend ages searching the threads and posts and not found an answer to this type of question.