ok great, have added that to the pp_confirm page. on the confirm page there was already a reference to TotalPrice (see http://prntscr.com/cd7t33 ) and have tentatively added another as not sure what to do
$WA_PP_ECO_Set_params[0][$nextIndex] = "OrderValueBeforeDiscount";
$WA_PP_ECO_Set_params[1][$nextIndex] = "".$motley->TotalPrice() ."";
cheers