219Counterclaim or set-off when co-plaintiff wrongly

219 Counterclaim or set-off when co-plaintiff wrongly (a) a person has been incorrectly or unnecessarily included as a co- plaintiff in a proceeding; and (b) the defendant has set up a counterclaim or set–off. (2) The defendant may get the benefit of the counterclaim or set-off by proving the claim or set-off against the parties other than the co-plaintiff. (3) The defendant’s entitlement under subrule (2) is not affected by— (a) the inclusion of the co-plaintiff; or (b) any proceeding resulting from the inclusion.