"Who would you hold criminally responsible as there is more than one director?"
All of them.
"Will SCL now close?"
ICO has already said it won't make any difference. That was plainly stated in the headline.
"If it does what legal rights do the ICO have?"
It's not so much rights as authority. It has the authority to go after those who were officers of the company when the offence occurred.
"Would a judge side with the ICO?"
Side isn't the right word. Judges are impartial and will impartially conduct the relevant tribunal. If the defence haven't a leg to stand on (or, indeed, f they have) they'll proceed according to the law.
"What if they claim they don't have the data to give?"
They'll need to prove that they never had it, difficult given what they already supplied, so either they give it or they admit to having destroyed evidence which would be an offence in itself.
"I don't think they'll get anything."
Who's they? I think SCL or its directors are going to get what's coming to them.