Yes there is no such think as a joint claim. Every claim must have a claimant.
I suppose where a partner has signed or completed a claim form you could state that they have made a false statement, but when it comes to the duty to notify changes of circusmtances this duty is made explicit in the regulations and only extends to the claimant, so a partner cannot be guilty of failing to notify a change as they have no legal duty to do so.
