Ask your bank for a microfilm copy of the cheque which they should be able to provide. They will have information on where the cheque was paid in so will be able to retrieve a copy based on this info. There is no breach of data protection here because you are only obtaining info regarding a payment into YOUR account. I used to manage a department for a major bank and we processed requests like this all the time. You may be charged a small fee for this. Alternatively, ask for a copy of the paying in slip which accompanied the cheque as this may bear a signature.