iad cailleadh, iad subject, cailleadh intransitive verbal noun
e.g. (I prefer) that they lose, (I want) them to lose, or here: if they lost
iad a chailleadh only for transitive constructions: iad object, cailleadh transitive verbal noun
e.g. (I want) to lose them, or here: if they were lost

In other dialects, there is only iad a chailleadh, transitively and intransitively (if applicable)
At least in Connacht, I'd prefer intransitive go gcaillidís, too.