Where a defendant against whom a claim could have been brought has died and —
(a) a grant of probate or administration has been made, the claim must be brought against the persons who are the personal representatives of the deceased;
(b) a grant of probate or administration has not been made —
(i) the claim must be brought against 'the estate of' the deceased, and
(ii) the claimant must apply to the court for an order appointing a person to represent the estate of the deceased in the claim.