Switching Direct Debits

Paragon

I recently switched a few of my direct debits from one account to another, within the same bank using online banking. Now I want to switch the Direct Debits back to the original account, but HSBC won't let me switch them back to the original account so I have had to go to each company involved and ask them to change my details. It is not yet clear whether this is clear.

I wish I'd left it all alone now, but why does HSBC restict DD switching so much?

Would it work if I switched them again to a 3rd account - would that mean I could get them back to the account they originally came from?! Depends on the definition of 'original' i suppose!