cew: Hi is there such a thing.
Despite my response to your other thread I am no longer 100% confident that a joint savings account wouldn't end up as linked even if that is down to bank incompetence. Having re-read the Experian FAQ this whole linking thing is even scarier than I thought. You are right to be concerned.
I'm not sure if there is a savings acount which does what you want.
Possibly the way out of this is for one of you to have a sole basic bank account only for the houshold direct debits and both parties fund it in which ever way you agree making sure its not used for anything else.
Two people living at the same address, not having a joint account or ever making a joint application for credit are not grounds for a financial association.