Henry J was required to consider whether the amendments added a new cause of action and if leave should be given under r.376 of the Uniform Civil Procedure Rules 1999 (Qld)(“UCPR”) and or s 81 of the Supreme Court of Queensland Act 1991 (Qld)..
His Honour noted:
 The term “cause of action” in r 376 does not merely include the category of action involved, for example, damages for personal injury occasioned by negligence. It also includes facts which are material to proof of the elements of the action. As much was explained by PD McMurdo J in Borsato v Campbell where his Honour said:
“The term “cause of action” was defined in Cooke v Gill (1873) LR 8 CP 107 at 116 as being “every fact which is material to be proved to entitle the plaintiff to succeed”, a definition which many judgments have employed in the context of this rule or its equivalent: see e.g. Allonnor Pty Ltd v Doran  QCA 372 at  per McPherson JA. But it has not been applied literally, for otherwise any new fact to be added to a plaintiff’s case would be treated as raising a new cause of action which required leave in the context of a rule such as r 376(4). So in Allonnor Pty Ltd v Doran for example, there is an indication of what the Court of Appeal in Thomas v State of Queensland  QCA 336 at  subsequently endorsed as a “fairly broad brush comparison between the nature of the original claim and that to which it is sought to be amended”. The dividing line is between the addition of facts which involve a new cause of action and those which are simply further particulars of the cause already claimed, and its location involves a question of degree which can be argued, one way or the other, by the level of abstraction at which a plaintiff’s case is described.”
His Honour considered each amendment and in respect of some found that “…they involve more detailed pleading of the same pathway to liability already pleaded…” and leave to plead was not required pursuant to r 376. 
However, in respect of other amendments His Honour found that they pleaded “…a different pathway to liability than that hitherto…” and that leave was required.
His Honour found that it did arise out of substantially the same facts and hence leave was given, but considered the tidier mechanism to do so was to strike out the amended claim and give leave to replead afresh.
David Cormack – Brisbane Barrister & Mediator