The Bank could only provide a printout of the cheque if it was deposited, and it costs £12 to get one. All it shows is the name of the recipient, not the account number its gone into. If you believe your MIL is capable of calling up Customer Services and would agree to pay the £12 fee for a print out, then send her a stamped addressed envelope to enable her to send you the print out to examine yourself. Your husband is correct, try not to let this upset you. Why would it? You are supported by your OH and you don't even like your MIL ( I assume). Does your OH confront his mother?