If you knew anything about banking you would know that you cannot set the frequency of a DD. You can only request a convenient date. Many time I hav been charged because a company took money from my account 48 hours earlier than they should have done. DDs are controlled by the companies and basically give them carte blanch to take what they want when they want. And the banks arent very sympathetic after the 4th or 5th occasion.
I have had my bank account for 10 years. I called my direct debit providers and told them to always take the payment on the 23rd of each month. Not once have they ever taken the direct debit early. I think that you may have an issue with the direct debit provider as opposed to your bank. If they do not take it on the date agreed with you they are liable to pay any charges you get as a result