BREWERDAVE1: I have had it confirmed to me that any due rebate will be paid by cheque NOT BACS transfer to the bank account
When I saw that on the SP website I hoped it was out of date information. It's certainly a dated procedure. Far rather be subjected to the vagaries of a DD mandate than "cheque in the post".
Don't know how widespread Scottish Power "cheque in the post" is, but Southern Electric refund by BACS gets my vote.